Treatment of bronchiolitis is usually focused on the symptoms instead of the infection itself since the infection will run its course and complications are typically from the symptoms themselves. Without active treatment half of cases will go away in 13 days and 90% in three weeks.

Measures for which the evidence is unclear include nebulized epinephrine, nasal suctioning, and nebulized hypertonic saline. Treatments which the evidence does not support include salbutamol, steroids, antibiotics, antivirals, chest physiotherapy, and cool mist.

Currently other medications do not yet have evidence to support their use. Ribavirin is an antiviral drug which does not appear to be effective for bronchiolitis. Antibiotics are often given in case of a bacterial infection complicating bronchiolitis, but have no effect on the underlying viral infection. Corticosteroids have no proven benefit in bronchiolitis treatment and are not advised. DNAse has not been found to be effective.

Most patients recover with corticosteroid therapy. A standardized approach to dosing starting at 0.75 mg/kg and weaning over 24 weeks has been shown to reduce total corticosteroid exposure without affecting outcome.

About two thirds of patients recover with corticosteroid therapy: the usual corticosteroid administered is prednisolone in Europe and prednisone in the USA; these differ by only one functional group and have the same clinical effect. The corticosteroid is initially administered in high dosage, typically 50 mg per day tapering down to zero over a six-month to one-year period. If the corticosteroid treatment is halted too quickly the disease may return. Other medications must be taken to counteract side effects of the steroid.

There should also be a "care plan" in case of future exacerbations. Patients may watch for symptoms, such as shortness of breath, change in character or amount of mucus, and start self-treatment as discussed with a health care provider. This allows for treatment right away until a doctor can be seen.

The symptoms of acute exacerbations are treated using short-acting bronchodilators. A course of corticosteroids, usually in tablet or intravenous rather than inhaled form, can speed up recovery. The IV and oral forms of steroids have been found to be equivalent. Antibiotics are often used but will only help if the exacerbation is due to an infection. Antibiotics are indicated when a patient notes increased sputum production, purulent sputum, increased dyspnea, has an elevated white count, or is febrile. Examples of first-line antibiotics are amoxicillin, doxycycline and co-trimoxazole.

Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommended in children less than six years of age. There is tentative evidence that salbutamol may be useful in those with wheezing; however, it may result in nervousness and tremors. Antibiotics should generally not be used. An exception is when acute bronchitis is due to pertussis. Tentative evidence supports honey and pelargonium to help with symptoms. Getting plenty of rest and fluids is also often recommended.

Oxygen therapy should be initiated if there is significantly low blood oxygen. High flow oxygen may be harmful in those with an acute exacerbation of COPD. In the prehospital environment those given high flow O rather than titrating their O saturations to 88% to 92% had worse outcomes.

"N"-Acetylcysteine (NAC) is a precursor to glutathione, an antioxidant. It has been hypothesized that treatment with high doses of NAC may repair an oxidant–antioxidant imbalance that occurs in the lung tissue of patients with IPF. In the first clinical trial of 180 patients (IFIGENIA), NAC was shown in previous study to reduce the decline in VC and DLCO over 12 months of follow-up when used in combination with prednisone and azathioprine (triple therapy).

More recently, a large randomized, controlled trial (PANTHER-IPF) was undertaken by the National Institutes of Health (NIH) in the USA to evaluate triple therapy and NAC monotherapy in IPF patients. This study found that the combination of prednisone, azathioprine, and NAC increased the risk of death and hospitalizations and the NIH announced in 2012 that the triple-therapy arm of the PANTHER-IPF study had been terminated early.

This study also evaluated NAC alone and the results for this arm of the study were published in May 2014 in the New England Journal of Medicine, concluding that "as compared with placebo, acetylcysteine offered no significant benefit with respect to the preservation of FVC in patients with idiopathic pulmonary fibrosis with mild-to-moderate impairment in lung function".

Corticosteroids are usually used in inhaled form, but may also be used as tablets to treat and prevent acute exacerbations. While inhaled corticosteroids (ICSs) have not shown benefit for people with mild COPD, they decrease acute exacerbations in those with either moderate or severe disease. By themselves, they have no effect on overall one-year mortality. Whether they affect the progression of the disease is unknown. When used in combination with a LABA, they may decrease mortality compared to either ICSs or LABA alone. Inhaled steroids are associated with increased rates of pneumonia. Long-term treatment with steroid tablets is associated with significant side effects.

A Cochrane review comparing pirfenidone with placebo, found a reduced risk of disease progression by 30%. FVC or VC was also improved, even if a mild slowing in FVC decline could be demonstrated only in one of the two CAPACITY trials. A third study, which was completed in 2014 found reduced decline in lung function and IPF disease progression. The data from the ASCEND study were also pooled with data from the two CAPACITY studies in a pre-specified analysis which showed that pirfenidone reduced the risk of death by almost 50% over one year of treatment.

This disease is irreversible and severe cases often require a lung transplant. Transplant recipients are at risk for re-developing the disease, as bronchiolitis obliterans is a common complication of chronic rejection. Evaluation of interventions to prevent bronchiolitis obliterans relies on early detection of abnormal spirometry results or unusual decreases in repeated measurements.

A multi-center study has shown the combination of inhaled fluticasone propionate, oral montelukast, and oral azithromycin may be able to stabilize the disease and slow disease progression. This has only been studied in patients who previously underwent hematopoietic stem cell transplantation.

Inhaled bronchodilators are the primary medications used, and result in a small overall benefit. The two major types are β agonists and anticholinergics; both exist in long-acting and short-acting forms. They reduce shortness of breath, wheeze, and exercise limitation, resulting in an improved quality of life. It is unclear if they change the progression of the underlying disease.

In those with mild disease, short-acting agents are recommended on an as needed basis. In those with more severe disease, long-acting agents are recommended. Long-acting agents partly work by improving hyperinflation. If long-acting bronchodilators are insufficient, then inhaled corticosteroids are typically added. With respect to long-acting agents, if tiotropium (a long-acting anticholinergic) or long-acting beta agonists (LABAs) are better is unclear, and trying each and continuing the one that worked best may be advisable. Both types of agent appear to reduce the risk of acute exacerbations by 15–25%. While both may be used at the same time, any benefit is of questionable significance.

Several short-acting β agonists are available, including salbutamol (albuterol) and terbutaline. They provide some relief of symptoms for four to six hours. Long-acting β agonists such as salmeterol, formoterol, and indacaterol are often used as maintenance therapy. Some feel the evidence of benefits is limited while others view the evidence of benefit as established. Long-term use appears safe in COPD with adverse effects include shakiness and heart palpitations. When used with inhaled steroids they increase the risk of pneumonia. While steroids and LABAs may work better together, it is unclear if this slight benefit outweighs the increased risks. Indacaterol requires an inhaled dose once a day, and is as effective as the other long-acting β agonist drugs that require twice-daily dosing for people with stable COPD.

Two main anticholinergics are used in COPD, ipratropium and tiotropium. Ipratropium is a short-acting agent, while tiotropium is long-acting. Tiotropium is associated with a decrease in exacerbations and improved quality of life, and tiotropium provides those benefits better than ipratropium. It does not appear to affect mortality or the overall hospitalization rate. Anticholinergics can cause dry mouth and urinary tract symptoms. They are also associated with increased risk of heart disease and stroke. Aclidinium, another long acting agent, reduces hospitalizations associated with COPD and improves quality of life. Aclinidinium has been used as an alternative to tiotropium, but which drug is more effective is not known.

Specific pretreatments, drugs to prevent chemically induced lung injuries due to respiratory airway toxins, are not available. Analgesic medications, oxygen, humidification, and ventilator support currently constitute standard therapy. In fact, mechanical ventilation remains the therapeutic mainstay for acute inhalation injury. The cornerstone of treatment is to keep the PaO2 > 60 mmHg (8.0 kPa), without causing injury to the lungs with excessive O2 or volutrauma. Pressure control ventilation is more versatile than volume control, although breaths should be volume limited, to prevent stretch injury to the alveoli. Positive end-expiratory pressure (PEEP) is used in mechanically ventilated patients with ARDS to improve oxygenation. Hemorrhaging, signifying substantial damage to the lining of the airways and lungs, can occur with exposure to highly corrosive chemicals and may require additional medical interventions. Corticosteroids are sometimes administered, and bronchodilators to treat bronchospasms. Drugs that reduce the inflammatory response, promote healing of tissues, and prevent the onset of pulmonary edema or secondary inflammation may be used following severe injury to prevent chronic scarring and airway narrowing.

Although current treatments can be administered in a controlled hospital setting, many hospitals are ill-suited for a situation involving mass casualties among civilians. Inexpensive positive-pressure devices that can be used easily in a mass casualty situation, and drugs to prevent inflammation and pulmonary edema are needed. Several drugs that have been approved by the FDA for other indications hold promise for treating chemically induced pulmonary edema. These include β2-agonists, dopamine, insulin, allopurinol, and non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. Ibuprofen is particularly appealing because it has an established safety record and can be easily administered as an initial intervention. Inhaled and systemic forms of β2-agonists used in the treatment of asthma and other commonly used medications, such as insulin, dopamine, and allopurinol have also been effective in reducing pulmonary edema in animal models but require further study. A recent study documented in the "AANA Journal" discussed the use of volatile anesthetic agents, such as sevoflurane, to be used as a bronchodilator that lowered peak airway pressures and improved oxygenation. Other promising drugs in earlier stages of development act at various steps in the complex molecular pathways underlying pulmonary edema. Some of these potential drugs target the inflammatory response or the specific site(s) of injury. Others modulate the activity of ion channels that control fluid transport across lung membranes or target surfactant, a substance that lines the air sacs in the lungs and prevents them from collapsing. Mechanistic information based on toxicology, biochemistry, and physiology may be instrumental in determining new targets for therapy. Mechanistic studies may also aid in the development of new diagnostic approaches. Some chemicals generate metabolic byproducts that could be used for diagnosis, but detection of these byproducts may not be possible until many hours after initial exposure. Additional research must be directed at developing sensitive and specific tests to identify individuals quickly after they have been exposed to varying levels of chemicals toxic to the respiratory tract.

Currently there are no clinically approved agents that can reduce pulmonary and airway cell dropout and avert the transition to pulmonary and /or airway fibrosis.

Evidence suggests that the decline in lung function observed in chronic bronchitis may be slowed with smoking cessation. Chronic bronchitis is treated symptomatically and may be treated in a nonpharmacologic manner or with pharmacologic therapeutic agents. Typical nonpharmacologic approaches to the management of COPD including bronchitis may include: pulmonary rehabilitation, lung volume reduction surgery, and lung transplantation. Inflammation and edema of the respiratory epithelium may be reduced with inhaled corticosteroids. Wheezing and shortness of breath can be treated by reducing bronchospasm (reversible narrowing of smaller bronchi due to constriction of the smooth muscle) with bronchodilators such as inhaled long acting β-adrenergic receptor agonists (e.g., salmeterol) and inhaled anticholinergics such as ipratropium bromide or tiotropium bromide. Mucolytics may have a small therapeutic effect on acute exacerbations of chronic bronchitis. Supplemental oxygen is used to treat hypoxemia (too little oxygen in the blood) and has been shown to reduce mortality in chronic bronchitis patients. Oxygen supplementation can result in decreased respiratory drive, leading to increased blood levels of carbon dioxide (hypercapnia) and subsequent respiratory acidosis.

Evidence does not support the general use of antibiotics in acute bronchitis. While some evidence suggests antibiotics speed up resolution of the cough by about 12 hours there is a greater risk of gastrointestinal problems and no change in longer term outcomes. Antibiotics use also leads to the promotion of antibiotic-resistant bacteria, which increase morbidity and mortality.

ILD is not a single disease, but encompasses many different pathological processes. Hence treatment is different for each disease.

If a specific occupational exposure cause is found, the person should avoid that environment. If a drug cause is suspected, that drug should be discontinued.

Many cases due to unknown or connective tissue-based causes are treated with corticosteroids, such as prednisolone. Some people respond to immunosuppressant treatment. Patients with a low level of oxygen in the blood may be given supplemental oxygen.

Pulmonary rehabilitation appears to be useful. Lung transplantation is an option if the ILD progresses despite therapy in appropriately selected patients with no other contraindications.

On October 16, 2014, the Food and Drug Administration approved a new drug for the treatment of Idiopathic Pulmonary Fibrosis (IPF). This drug, Ofev (nintedanib), is marketed by Boehringer Ingelheim Pharmaceuticals, Inc. This drug has been shown to slow the decline of lung function although the drug has not been shown to reduce mortality or improve lung function. The estimated cost of the drug per year is approximately $94,000.

Antibiotics improve outcomes in those with bacterial pneumonia. Antibiotic choice depends initially on the characteristics of the person affected, such as age, underlying health, and the location the infection was acquired. In the UK, treatment before culture results with amoxicillin is recommended as the first line for community-acquired pneumonia, with doxycycline or clarithromycin as alternatives. In North America, where the "atypical" forms of community-acquired pneumonia are more common, macrolides (such as azithromycin or erythromycin), and doxycycline have displaced amoxicillin as first-line outpatient treatment in adults. In children with mild or moderate symptoms, amoxicillin remains the first line. The use of fluoroquinolones in uncomplicated cases is discouraged due to concerns about side-effects and generating resistance in light of there being no greater clinical benefit.

For those who require hospitalization and caught their pneumonia in the community the use of a β-lactam such as cephazolin plus macrolide such as azithromycin or a fluoroquinolones is recommended. The addition of corticosteroids also appears to improve outcomes.

The duration of treatment has traditionally been seven to ten days, but increasing evidence suggests that shorter courses (three to five days) are similarly effective. Recommendations for hospital-acquired pneumonia include third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin. These antibiotics are often given intravenously and used in combination. In those treated in hospital, more than 90% improve with the initial antibiotics.

Oral antibiotics, rest, simple analgesics, and fluids usually suffice for complete resolution. However, those with other medical conditions, the elderly, or those with significant trouble breathing may require more advanced care. If the symptoms worsen, the pneumonia does not improve with home treatment, or complications occur, hospitalization may be required. Worldwide, approximately 7–13% of cases in children result in hospitalization, whereas in the developed world between 22 and 42% of adults with community-acquired pneumonia are admitted. The CURB-65 score is useful for determining the need for admission in adults. If the score is 0 or 1, people can typically be managed at home; if it is 2, a short hospital stay or close follow-up is needed; if it is 3–5, hospitalization is recommended. In children those with respiratory distress or oxygen saturations of less than 90% should be hospitalized. The utility of chest physiotherapy in pneumonia has not yet been determined. Non-invasive ventilation may be beneficial in those admitted to the intensive care unit. Over-the-counter cough medicine has not been found to be effective nor has the use of zinc in children. There is insufficient evidence for mucolytics.

Treatment of CAP in children depends on the child's age and the severity of illness. Children under five are not usually treated for atypical bacteria. If hospitalization is not required, a seven-day course of amoxicillin is often prescribed, with co-trimaxazole an alternative when there is allergy to penicillins. Further studies are needed to confirm the efficacy of newer antibiotics. With the increase in drug-resistant Streptococcus pneumoniae, antibiotics such as cefpodoxime may become more popular. Hospitalized children receive intravenous ampicillin, ceftriaxone or cefotaxime, and a recent study found that a three-day course of antibiotics seems sufficient for most mild-to-moderate CAP in children.

Flock worker's lung can be prevented with engineering controls that protect workers from inhaling flock. Engineering controls to prevent inhalation of flock can include using guillotine cutters rather than rotary cutters, and ensuring that blades are sharp, since dull blades shear off more respirable particles. Flocking plants have also implemented medical surveillance programs for workers to diagnose cases at an earlier stage. Another technique for preventing flock worker's lung is cleaning the workplace with alternatives to compressed air in order to avoid resuspending particulates in the air.

Macrolide antibiotics, such as erythromycin, are an effective treatment for DPB when taken regularly over an extended period of time. Clarithromycin or roxithromycin are also commonly used. The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through immunomodulation (adjusting the immune response), which can be achieved by taking the antibiotics in low doses. Treatment consists of daily oral administration of erythromycin for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and blood gas (an arterial blood test that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range. Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant "P. aeruginosa". However, DPB symptoms usually return, and treatment would need to be resumed. Although highly effective, erythromycin may not prove successful in all individuals with the disease, particularly if macrolide-resistant "P. aeruginosa" is present or previously untreated DPB has progressed to the point where respiratory failure is occurring.

With erythromycin therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only neutrophil proliferation, but also lymphocyte activity and obstructive mucus and water secretions in airways. The antibiotic effects of macrolides are not involved in their beneficial effects toward reducing inflammation in DPB. This is evident because the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant "P. aeruginosa", erythromycin therapy still reduces inflammation.

A number of factors are involved in suppression of inflammation by erythromycin and other macrolides. They are especially effective at inhibiting the proliferation of neutrophils, by diminishing the ability of interleukin 8 and leukotriene B4 to attract them. Macrolides also reduce the efficiency of adhesion molecules that allow neutrophils to stick to bronchiolar tissue linings. Mucus production in the airways is a major culprit in the morbidity and mortality of DPB and other respiratory diseases. The significant reduction of inflammation in DPB attributed to erythromycin therapy also helps to inhibit the production of excess mucus.

Most newborn infants with CAP are hospitalized, receiving IV ampicillin and gentamicin for at least ten days to treat the common causative agents "streptococcus agalactiae", "listeria monocytogenes" and "escherichia coli". To treat the herpes simplex virus, IV acyclovir is administered for 21 days.

Most cases are self-limited and resolve themselves in a few weeks.

In cases of viral pneumonia where influenza A or B are thought to be causative agents, patients who are seen within 48 hours of symptom onset may benefit from treatment with oseltamivir or zanamivir. Respiratory syncytial virus (RSV) has no direct acting treatments, but ribavirin in indicated for severe cases. Herpes simplex virus and varicella-zoster virus infections are usually treated with aciclovir, whilst ganciclovir is used to treat cytomegalovirus. There is no known efficacious treatment for pneumonia caused by SARS coronavirus, MERS coronavirus, adenovirus, hantavirus, or parainfluenza. Care is largely supportive.

Flock worker's lung is generally treated by removing the individual from the environment where they are inhaling flock. Symptoms generally improve within days to weeks after stopping exposure. The benefits of glucocorticoid therapy are unclear.

Flock worker's lung may raise the risk for lung cancer, but the connection is a topic of research as of 2015. The disease can be subacute or develop over long periods of exposure.

There is evidence to show that steroids given to babies less than 8 days old can prevent bronchopulmonary dysplasia. However, the risks of treatment may outweigh the benefits.

It is unclear if starting steroids more than 7 days after birth is harmful or beneficial. It is thus recommended that they only be used in those who cannot be taken off of a ventilator.