Wet-tail is a disease in the animal's intestines caused by the bacteria, "Lawsonia intracellularis". Wet-tail is a stress related illness—such stress can be caused by a variety of factors, including:

- Too much handling

- Change in environment

- Change in diet

- Extremely unclean caging

- Being away from mother and/or siblings

- Illness or death of a pair-bond or mate

As many as 90% of Americans and 92% of teenagers use antiperspirants or deodorants. In 2014, the global market for deodorants was estimated at 13.00 billion USD with a compound annual growth rate of 5.62% between 2015 and 2020.

Body odor may be reduced or prevented or even aggravated by using deodorants, antiperspirants, disinfectants, underarm liners, triclosan, special soaps or foams with antiseptic plant extracts such as ribwort and liquorice, chlorophyllin ointments and sprays topically, and chlorophyllin supplements internally. Although body odor is commonly associated with hygiene practices, its presentation can be affected by changes in diet as well as the other factors.

Wet-tail or proliferative ileitis, is a disease of hamsters. It is precipitated by stress. Even with treatment, the animal can die within 48–72 hours. Baby hamsters are much more likely to get the disease than older hamsters. It commonly is found when the hamster is being weaned at about four weeks of age.

Dysmelia can be caused by

- inheritance of abnormal genes, e.g. polydactyly, ectrodactyly or brachydactyly, symptoms of deformed limbs then often occur in combination with other symptoms (syndromes)

- external causes during pregnancy (thus not inherited), e.g. via amniotic band syndrome

- teratogenic drugs (e.g. thalidomide, which causes phocomelia) or environmental chemicals

- ionizing radiation (nuclear weapons, radioiodine, radiation therapy)

- infections

- metabolic imbalance

There is no known cure or treatment for the disorder.

The metabolic and clinical manifestations of TMAU are generally regarded as benign, as there is no associated organ dysfunction. This

designation, and the fact that the condition is often unrecognised by doctors, can have important ramifications including missed or delayed diagnosis.

Affected individuals experience shame and embarrassment, fail to maintain relationships, avoid contact with people who comment on their condition, and are obsessive about masking the odour with hygiene products and even smoking. The malodorous aspect can have serious and destructive effects on schooling, personal life, career and relationships, resulting in social isolation, low self-esteem, depression, paranoid behaviour, and suicide. Delayed diagnosis, body odour and the lack of cure may lead to psychosocial issues. When the condition is suspected or known to occur in a family, genetic testing can be helpful in identifying the specific individuals who have or carry the disorder.

Ways of reducing the fishy odor may include:

- Avoiding foods such as egg yolks, legumes, red meats, fish, beans and other foods that contain choline, carnitine, nitrogen, sulfur and lecithin

- Taking low doses of antibiotics such as neomycin and metronidazole in order to reduce the amount of bacteria in the gut

- Using slightly acidic detergent with a pH between 5.5 and 6.5

Additionally, at least one study has suggested that daily intake of the supplements activated charcoal and copper chlorophyllin may improve the quality of life of individuals afflicted with TMAU by helping their bodies to oxidize and convert TMA to the odorless "N"-oxide (TMAO) metabolite. Study participants experienced subjective reduction in odor as well as objective reduction in TMA and increase in TMAO concentration measured in their urine. The study found that:

- 85% of test participants experienced complete loss of detectable "fishy" odor

- 10% experienced some reduction in detectable odor

- 5% did not experience any detectable odor reduction

Dysmelia can refer to

- missing (aplasia) limbs: amelia, oligodactyly, congenital amputation e.g. Tibial or Radial aplasia

- malformation of limbs: shortening (micromelia, rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot

- too many limbs: polymelia, polydactyly, polysyndactyly

- others: Tetraamelia, hemimelia, Symbrachydactyly

Local damage and inflammation that interferes with the taste buds or local nervous system such as that stemming from radiation therapy, glossitis, tobacco use, and denture use also cause ageusia. Other known causes include loss of taste sensitivity from aging (causing a difficulty detecting salty or bitter taste), anxiety disorder, cancer, renal failure and liver failure.

When untreated, the prognosis for ORS is generally poor. It is chronic, lasting many years or even decades with worsening of symptoms rather than spontaneous remission. Transformation to another psychiatric condition is unlikely, although very rarely what appears to be ORS may later manifest into schizophrenia, psychosis, mania, or major depressive disorder. The most significant risk is suicide.

When treated, the prognosis is better. In one review, the proportion of treated ORS cases which reported various outcomes were assessed. On average, the patients were followed for 21 months (range: 2 weeks to 10 years). With treatment, 30% recovered (i.e. no longer experienced ORS odor beliefs and thoughts of reference), 37% improved and in 33% there was a deterioration in the condition (including suicide) or no change from the pre-treatment status.

Measurement of urine for the ratio of trimethylamine to trimethylamine oxide is the standard screening test. A blood test is available to provide genetic analysis. The prominent enzyme responsible for TMA N-oxygenation is coded by the "FMO3" gene.

False positives can occur in the following conditions, where elevated TMA can be present in the urine without any underlying TMAU:

- Urinary tract infection

- Bacterial vaginosis

- Cervical cancer

- Advanced liver or kidney disease

A similar foul-smelling odor of the urine has also been associated with colonization of the urinary tract with a bacterium called "Aerococcus urinae", especially in children.

Deficiency of vitamin B (niacin) and zinc can cause problems with the endocrine system, which may cause taste loss or alteration. Disorders of the endocrine system, such as Cushing's syndrome, hypothyroidism and diabetes mellitus, can cause similar problems. Ageusia can also be caused by medicinal side-effects from antirheumatic drugs such as penicillamine, antiproliferative drugs such as cisplatin, ACE inhibitors, and other drugs including azelastine, clarithromycin, terbinafine, and zopiclone.

One theory (Kristina Palacio) explains "usog" in terms of child distress that leads to greater susceptibility to illness and diseases. There are observations that a stranger (or a newcomer or even a visiting relative) especially someone with a strong personality (physically big, boisterous, has strong smell, domineering, etc.) may easily distress a child. Thus, the child is said to be "overpowered" or "nauusog" and thus may feel afraid, develop fever, get sick, etc.

In "usog", the child's distress is the consequence of the child's failure to adapt to change. It is, in medical terms, the consequence of the disruption of homeostasis through physical or psychological stimuli brought about by the stranger. Technically, the condition results from the child-environment interaction that leads the child to perceive a painful discrepancy, real or imagined, between the demands of a situation on the one hand and their social, biological, or psychological resources on the other. The stressful stimuli to the child may be mental (stranger is perceived as a threat, malevolent or demanding), physiological (loud and/or high-pitched voice of the stranger that is hurting to the child's eardrum; strong smell of the stranger that irritates the child's nasal nerves), or physical (stranger has heavy hands or is taking up too much space).

The stranger's act of gently placing his finger with his saliva to the child's arm, foot, or any particular part of the child's body, could make him more familiar to the child, and thus, reduce if not remove the stress. As the stranger keeps gently saying, "Pwera usog... pwera usog...," the child is made to feel and assured that he means no harm. The "usog" is said to be counteracted because the child is prevented from succumbing to an illness since the child is no longer in distress. Children or even adults who are shy or have weak personalities are more susceptible to "usog" in accordance with observations and theory. Some have observed that at times even praising a shy child by a visiting relative caused an "usog".

The saliva from the stranger, granted that he or she is healthy and consistent with his or her oral hygiene, is relatively clean and contains enough antimicrobial compounds such as lactoferrin, lactoperoxidase, and secretory immunoglobulin A which can help clear pathogens from the child and benefit the child against infection. Furthermore, human saliva has opiorphin, a newly researched pain-killing substance. Initial research with mice shows the compound has a painkilling effect of up to six times that of morphine. It works by stopping the normal breakdown of natural pain-killing opioids in the spine, called enkephalins. Opiorphin in human saliva is a relatively simple molecule, and the child's immune system may trigger a biochemical cascade (complement system) to produce other stress-reducing compounds.

Usog can also, though less commonly, affect adults, and it may induce vomiting and stomach ache rather than fever. Supposedly, it can be prevented by stopping a stranger or visitor from greeting the person.

Unlike "lihi", however, usog is not yet medically accepted. More than the superstitious folks, researchers dealing with Filipino Psychology say they have observed this phenomenon with regularity and suggest that this be added to the Psychiatric Disorders Handbook DSM-V.

Cases have been reported from many different countries around the world. It is difficult to estimate the prevalence of ORS in the general population because data are limited and unreliable, and due to the delusional nature of the condition and the characteristic secrecy and shame.

For unknown reasons, males appear to be affected twice as commonly as females. High proportions of ORS patients are unemployed, single, and not socially active. The average age reported is around 20–21 years, with almost 60% of cases occurring in subjects under 20 in one report, although another review reported an older average age for both males (29) and females (40).

Merciful anosmia is a condition in which the person is unaware of the foul smell emanating from his own nose. This condition is seen in atrophic rhinitis. In atrophic rhinitis, the turbinates, venous sinusoids, seromucinous glands and nerves undergo atrophy, resulting in a foul smelling discharge. As the nerve fibres sensing smell are also atrophied, the patient is unable to appreciate the foul smell.

The saree is common female attire in the Indian subcontinent. It is a piece of long (generally ) cloth which can be made of various materials: cotton, silk, nylon, chiffon or synthetic fabric. It is worn over an inner skirt (petticoat) which is tightened around the waist by a thick cotton cord. This is the traditional costume of most Indian women. The saree is attached to the waist throughout the day in the hot and humid climate. The waist is often soiled with dust and sweat and remains without proper cleaning. This causes changes in pigmentation and mild scaling over the waist. This, in turn, causes chronic irritation and gradually malignancy may develop in the skin at the waistline.

Usog or balis is a topic in psycho-medicine in Filipino Psychology (but considered just as a Filipino superstition in Western Psychology) where an affliction or psychological disorder is attributed to a greeting by a stranger, or an evil eye hex. It usually affects an unsuspecting child, usually an infant or toddler, who has been greeted by a visitor or a stranger.

In some limited areas, it is said that the condition is also caused by the stranger having an evil eye or "masamang mata" in Tagalog, lurking around. This may have been influenced by the advent of the Spaniards who long believed in the "mal de ojo" superstition.

Once affected, the child begins to develop fever, and sometimes convulsions. Supposedly, the child can be cured by placing its clothing in hot water and boiling it. In most other places, to counter the effects of the "usog" the stranger or newcomer is asked to put some of his or her saliva on the baby's abdomen, shoulder or forehead before leaving the house. The newcomer then leaves while saying: ""Pwera usog... pwera usog..."" The saliva is placed on the finger first, before the finger is rubbed on the baby's abdomen or forehead. The stranger is never to lick the child. The practice is that the stranger or visitor is asked to touch his or her finger with saliva to the child's body, arm or foot (""lawayan"") to prevent the child from getting overpowered (""upang hindi mausog"").

Tonsilloliths or tonsillar concretions occur in up to 10% of the population, frequently due to episodes of tonsillitis. While small concretions in the tonsils are common, true tonsilloliths or stones are rare. They commonly occur in young adults and are rare in children.

Saree cancer is a type of skin cancer that occurs along the waistline in females wearing the saree, caused by constant irritation which can result in scaling and changes in pigmentation of the skin. It is a rare type of cancer and generally found in the Indian subcontinent, where sarees are commonly worn by girls and women throughout their lives. It is similar to Marjolin's ulcer in cause, involving chronic inflammation.

A common cause of lick granuloma appears to be psychological, related to stress, anxiety, separation anxiety, boredom, or compulsiveness. Lick granulomas are especially seen in large active dogs left alone for long periods of time. It is often considered to be a form of canine obsessive-compulsive disorder.

But other less common causes include bacterial or fungal infections, trauma causing nerve damage, allergies, or joint disease. Hot spots may also lead to the formation of lick granulomas.

Many large breed dogs appear to be predisposed, as well as golden retrievers and other bird dogs. Most of the dogs with the condition are over five years of age. Seventy percent of the time it occurs on one of the dog's left legs. Arthritic and mobility problems in older dogs give them more time to lick and over-groom themselves.

Frequent formations of lick granulomas in the same area due to the constant licking will cause hardening, callous formation, hair loss (the hair may stop growing back), and hyperpigmentation to that area. The condition becomes a vicious cycle – erosion of the skin from licking leads to pain and itching, which leads to more licking. Lick granulomas sometimes become infected with bacteria, causing abscessed areas or fistulous tracts (furuncles).

Causes can be remembered by mnemonic HERNIA:

- Hereditary factors: the disease runs in families

- Endocrine imbalance: the disease tends to start at puberty and mostly involves females

- Racial factors: whites are more susceptible than natives of equatorial Africa

- Nutritional deficiency: vitamins A or D, or iron

- Infection: "Klebsiella ozaenae", diphtheroids, "Proteus vulgaris", "E. coli", etc.

- Autoimmune factors: viral infection or some other unidentified insult may trigger antigenicity of the nasal mucosa.

The disruption of olfaction and potential effects to survival and reproductive success at environmentally-relevant concentrations metals, pesticides or surfactants have implications for fish and salmon recovery because these are commonly found in western United States streams. Conventional, acute and chronic toxicity testing do not explicitly address nervous system function and underestimate thresholds for toxicity in salmonids. Since these effects are not explicitly looked at during studies they oftentimes can go unnoticed. Olfactory toxicity occurring at environmentally relevant concentrations can induce reduction to food odor attraction and predator scent or alarm response pheromones can cause major problems with survivorship. Olfactory toxicity can also affect the ability of anadromous fish to find their natal stream causing them to stray to other streams.

Treatment of the primary cause, if known, is essential.

In psychogenic cases, dealing with psychological factors is most important. Factors should be identified such as being left alone all day, being confined, and changes in the household. Correction of these causes may include increased walks, avoiding confinement, and more interaction in the home. Some veterinarians have proposed that diet can affect compulsive behaviors in dogs.

Drugs may be used until behavior modification has had time to take effect. Antidepressants are most commonly used, including doxepin, amitriptyline, fluoxetine, and clomipramine. If the psychological factors are not corrected, the pet will usually relapse after the drugs are discontinued. Endorphin blockers such as naltrexone can be used to reduce addiction to licking, or endorphin substitutes such as hydrocodone may decrease the urge to lick.

The animal should be tested for allergies, and treated accordingly if positive (fatty acids, antihistamines, hypoallergic diet, etc.). It may also be necessary to check thyroid levels, as hypothyroidism seems to play a role in some cases, particularly in black Labrador retrievers; thyroid medication often will resolve the problem if it's due to hypothyroidism.

The frequency of phantosmia is rare in comparison with the frequency of parosmia. Parosmia has been estimated to be in 10-60% of patients with olfactory dysfunction and from studies, it has been shown that it can last anywhere from 3 months to 22 years. Smell and taste problems result in over 200,000 visits to physicians annually in the US. Lately, it has been thought that phantosmia might co-occur with Parkinson's disease. However, its potential to be a premotor biomarker for Parkinson's is still up for debate as not all patients with Parkinson's disease have olfactory disorders

A longitudinal study on pregnant females found that 76% of pregnant females experienced significant changes in gustation and olfaction perception. This was found to be caused and linked to their pregnancy. The study concluded that 67% of the pregnant females had reported a higher level of sensitivity to smell, 17% suffered from an olfactory distortion and 14% suffered from phantosmia; these distortions were very minimal towards the last stages of pregnancy and in the majority were not present post partum. Furthermore, 26% of these participants also claimed that they also experienced an increased sensitivity to foods that were bitter and a decreased sensitivity to salt. These findings suggest that pregnant females experience distorted smell and taste perception during pregnancy. It has also been found that 75% of women alter their diets during pregnancy. Further research is being conducted to determine the mechanism behind food cravings during pregnancy.

A temporary loss of smell can be caused by a blocked nose or infection. In contrast, a permanent loss of smell may be caused by death of olfactory receptor neurons in the nose or by brain injury in which there is damage to the olfactory nerve or damage to brain areas that process smell (see olfactory system). The lack of the sense of smell at birth, usually due to genetic factors, is referred to as "congenital anosmia." Family members of the patient suffering from congenital anosmia are often found with similar histories; this suggests that the anosmia may follow an autosomal dominant pattern. Anosmia may very occasionally be an early sign of a degenerative brain disease such as Parkinson's disease and Alzheimer's disease.

Another specific cause of permanent loss could be from damage to olfactory receptor neurons because of use of certain types of nasal spray; i.e., those that cause vasoconstriction of the nasal microcirculation. To avoid such damage and the subsequent risk of loss of smell, vasoconstricting nasal sprays should be used only when absolutely necessary and then for only a short amount of time. Non-vasoconstricting sprays, such as those used to treat allergy-related congestion, are safe to use for prescribed periods of time. Anosmia can also be caused by nasal polyps. These polyps are found in people with allergies, histories of sinusitis & family history. Individuals with cystic fibrosis often develop nasal polyps.

Amiodarone is a drug used in the treatment of arrhythmias of the heart. A clinical study performed demonstrated that the use of this drug induced anosmia in some patients. Although rare, there was a case in which a 66-year-old male was treated with Amiodarone for ventricular tachycardia. After the use of the drug he began experiencing olfactory disturbance, however after decreasing the dosage of Amiodarone, the severity of the anosmia decreased accordingly hence correlating the use of Amiodarone to the development of anosmia.