Parasitic infections can usually be treated with antiparasitic drugs.

Albendazole and mebendazole have been the treatments administered to entire populations to control hookworm infection. However, it is a costly option and both children and adults become reinfected within a few months after deparasitation occurs raising concerns because the treatment has to repeatedly be administered and drug resistance may occur.

Another medication administered to kill worm infections has been pyrantel pamoate. For some parasitic diseases, there is no treatment and, in the case of serious symptoms, medication intended to kill the parasite is administered, whereas, in other cases, symptom relief options are used. Recent papers have also proposed the use of viruses to treat infections caused by protozoa.

The most common medications used to treat coccidian infections are in the sulfonamide antibiotic family.

Depending on the pathogen and the condition of the animal, untreated coccidiosis may clear of its own accord, or become severe and damaging, and sometimes cause death.

Drugs are frequently used to kill parasites in the host. In earlier times, turpentine was often used for this, but modern drugs do not poison intestinal worms directly. Rather, anthelmintic drugs now inhibit an enzyme that is necessary for the worm to make the substance that prevents the worm from being digested.

For example, tapeworms are usually treated with a medicine taken by mouth. The most commonly used medicine for tapeworms is praziquantel.

In regions where helminthiasis is common, mass deworming treatments may be performed, particularly among school-age children, who are a high-risk group. Most of these initiatives are undertaken by the World Health Organization (WHO) with positive outcomes in many regions. Deworming programs can improve school attendance by 25 percent. Although deworming improves the health of an individual, outcomes from mass deworming campaigns, such as reduced deaths or increases in cognitive ability, nutritional benefits, physical growth, and performance, are uncertain or not apparent.

Good hygiene is necessary to avoid reinfection. The Rockefeller Foundation's hookworm campaign in Mexico in the 1920s was extremely effective at eliminating hookworm from humans with the use of anthelmintics. However, preventative measures were not adequately introduced to the people that were treated. Therefore, the rate of reinfection was extremely high and the project evaluated through any sort of scientific method was a marked failure. More education was needed to inform the people of the importance of wearing shoes, using latrines (better access to sanitation), and good hygiene.

Intestinal parasite prevention methods are not isolated to specific geographical areas; however, many of the research-based interventions have primarily taken place in underdeveloped countries and regions, where sanitation is a large concern for spreading disease.Current best practice behaviors that prevent intestinal parasites include: using proper hand washing practices, using correctly-built latrines with ample ventilation, having a piped water source, and wearing shoes. Currently, in some parts of Ethiopia where disease prevalence is high, up to 80% of people in a population lack access to washing facilities. While is this high, 93% did have access to a latrine, but only 29.2% of those latrines had proper construction to decrease parasitic infections.Behavioral interventions have focused on promoting washing, sometimes with soap, in context of education at schools and child care facilities. In recent studies, the best interventions follow a multidisciplinary approach by:

- Increasing environmental sanitation to promote hand washing and shoe wearing habits

- Educating children at young ages at school and at home

Specific evidence-based interventions that may lower disease prevalence include:

- Interventions at schools, focusing on the construction of pit latrines (ventilated and improved), providing clean drinking water and educating the students about hygiene

- The SAFE (surgery, antibiotics, facial cleanliness, environmental sanitation) strategy to address trachoma, primarily the facial cleanliness and the environmental sanitation components

- Hand-washing with soap at critical times and nail clipping to decrease reinfection rates, although further research is needed to develop and implement similar interventions at scale

- Programs combining anthelmintic drug administration with interventions to increase environmental sanitation (such as decreasing fecal contamination)

Mammals can get parasites from contaminated food or water, bug bites, or sexual contact. Ingestion of contaminated water can produce Giardia infections.

Parasites normally enter the body through the skin or mouth. Close contact with pets can lead to parasite infestation as dogs and cats are host to many parasites.

Other risks that can lead people to acquire parasites are walking barefeet, inadequate disposal of feces, lack of hygiene, close contact with someone carrying specific parasites, and eating undercooked foods, unwashed fruits and vegetables or foods from contaminated regions.

Parasites can also be transferred to their host by the bite of an insect vector, i.e. mosquito, bed bug, fleas.

Coccidiosis is a significant disease for chickens, especially affecting the young chicks. It can be fatal or leave the bird with compromised digestion. There are chick feed mixes that contain a coccidiostat to manage exposure levels and control disease. In an outbreak, coccidiocidal medications are given. Examples are toltrazuril (Baycox) or amprolium. After multiple infections, surviving chickens become resistant to the coccidia.

The highest clearance rates are obtained by combining mebendazole or albendazole with ivermectin. Ivermectin's safety in children under and pregnant women has not yet been established.

People with diarrhea may be treated with loperamide to increase the amount of drug contact with the parasites.

Mebendazole is 90% effective in the first dose, and albendazole may also be offered as an anti-parasitic agent. Adding iron to the bloodstream helps solve the iron deficiency and rectal prolapse. Difetarsone is also an effective treatment.

Prevention and control measures to prevent soil-transmitted helminthiasis are the following: availability of clean water for personal and domestic uses, improved access to sanitation which includes the use of properly functioning and clean toilets by all community members, education on personal hygiene such as hand washing and hygienic and safe food preparation; eliminating the use of untreated human faeces as fertilizer.

They are treated with antiprotozoal agents. Recent papers have also proposed the use of viruses to treat infections caused by protozoa.

Broad-spectrum benzimidazoles (such as albendazole and mebendazole) are the first line treatment of intestinal roundworm and tapeworm infections. Macrocyclic lactones (such as ivermectin) are effective against adult and migrating larval stages of nematodes. Praziquantel is the drug of choice for schistosomiasis, taeniasis, and most types of food-borne trematodiases. Oxamniquine is also widely used in mass deworming programmes. Pyrantel is commonly used for veterinary nematodiasis. Artemisinins and derivatives are proving to be candidates as drugs of choice for trematodiasis.

Several public health prevention strategies could help lower the rates of metagonimiasis. One is to control the intermediate host (snails). This can be done through use of molluscidals. Another is to use education to ensure all people, especially in areas were the disease regularly occurs, fully cook all fish. This could potentially be problematic and not as effective as hoped as many of the people affected by metagonimiasis eat raw or pickled fish as part of a traditional, long-seated dietary practice. Additionally, implementing more sanitary water conditions would reduce the continual reintroduction of eggs to water sources, thus restarting the lifecycle. Complete control of metagonimiasis presents several potential problems because it does have several reservoir hosts, thus eradication is unlikely.

Limited access to essential medicine poses a challenge to the eradication of trichuriasis worldwide. Also, it is a public health concern that rates of post-treatment re-infection need to be determined and addressed to diminish the incidence of untreated re-infection. Lastly, with mass drug administration strategies and improved diagnosis and prompt treatment, detection of an emergence of antihelminthic drug resistance should be examined.

Mass Drug Administration (preventative chemotherapy) has had a positive effect on the disease burden of trichuriasis in East and West Africa, especially among children, who are at highest risk for infection.

Currently, no therapeutic drugs are prescribed for the disease. Therefore, prevention is the sole mode of treatment. This disease can only be prevented by quarantining sick birds and preventing migration of birds around the house, causing them to spread the disease. Deworming of birds with anthelmintics can reduce exposure to the cecal nematodes that carry the protozoan. Good management of the farm, including immediate quarantine of infected birds and sanitation, is the main useful strategy for controlling the spread of the parasitic contamination. The only drug used for the control (prophylaxis) in the United States is nitarsone at 0.01875% of feed until 5 days before marketing. Natustat and nitarsone were shown to be effective therapeutic drugs. Nifurtimox, a compound with known antiprotozoal activity, was demonstrated to be significantly effective at 300–400 ppm, and well tolerated by turkeys.

The World Health Organizations recommended albendazole or mebendazole for treatment.

Some treatments for infection with "Toxocara cati" include drugs designed to cause the adult worms to become partially anaesthetized and detach from the intestinal lining, allowing them to be excreted live in the feces. Such medications include piperazine and pyrantel. These are frequently combined with the drug praziquantel which appears to cause the worm to lose its resistance to being digested by the host animal. Other effective treatments include ivermectin, milbemycin, and selamectin. Dichlorvos has also been proven to be effective as a poison, though moves to ban it over concerns about its toxicity have made it unavailable in some areas.

Treatment for wild felids, however, is difficult for this parasite, as detection is the best way to find which individuals have the parasite. This can be difficult as infected species are hard to detect. Once detected, the infected individuals would have to be removed from the population, in order to lower the risk of continual exposure to the parasites.

A primary method that has been used to lower the amount of infection is removal through hunting. Removal can also occur through landowners, as Dare and Watkins (2012) discovered through their research on cougars. Both hunters and landowners can provide samples that can be used to detect the presence of feline roundworm in the area, as well as help remove it from the population. This method is more practical than administering medications to wild populations, as wild animals, as mentioned before, are harder to find in order to administer medicinal care.

Medicinal care, however, is also another method used in round worm studies; such as the experiment on managing raccoon roundworm done by Smyser et al. (2013) in which they implemented medical baiting. However, medicine is often expensive and the success of the baiting depends on if the infected individuals consume the bait. Additionally, it can be costly (in time and resources) to check on baited areas. Removal by hunting allows agencies to reduce costs and gives agencies a more improved chance of removing infected individuals.

Because of Eustrongylides species’ complex life cycle with various host species, preventing infection and controlling outbreaks is difficult. Outbreaks of this disease are closely linked to agricultural runoff and urban development Eutrophication of water bodies supports high population levels of oligochaete worms, which causes increased numbers of infected fish that eat the worms, and then the birds who eat the fish.

One way to prevent Eustrongylidosis is to control oligochaete populations. Outbreaks of this parasite are closely linked to high numbers of oligochaete worms in the area’s waterways. This is because the worms are essential for Eustrongylides species to reproduce. Oligochaete populations can be controlled by monitoring nutrient levels in the water, because high nutrient levels support oligochaete populations. They can also be controlled by decreasing the level of oxygen in the water. Encouraging responsible farming practices in order to reduce chemical run-off will help prevent this disease from occurring.

Managers need to be diligent in catching the symptoms of the parasite before it can become an outbreak. Once an outbreak of Eustrongylidosis has occurred, there is little that ecosystem managers can do to stop the spread in oligochaetes, fish and birds. Traditional anthelminthics (dewormers) are not effective in fish because they kill parasites that live inside the gastrointestinal tract, whereas Eustrongylides species live outside the stomach in the body cavity. The parasites can only be removed from fish surgically, which is not feasible. In order to completely stop the Eustrongylides life cycle in fish, all fish in an affected area must be culled.

Surgical removal of the parasite from wading birds is a viable option, but this would also not be feasible for a large number of birds, and it would not stop the cycle of infection.

Praziquantel is recommended in both adult and pediatric cases with dosages of 75 mg/kg/d in 3 doses for 1 day. Praziquantel is a Praziniozoquinoline derivative that alters the calcium flux through the parasite tectum and causes muscular paralysis and detachment of the fluke. Prizaquantel should be taken with liquids during a meal and as provided commercially as Biltricide. Praziquantel is not approved by the U.S. Food and Drug Administration (FDA) for treatment of metagonimiasis, but is approved for use on other parasitic infections.

Praziquantel has some side effects but they are generally relatively mild and transient and a review of evidence shows it overall a well-tolerated drug. Possible side effects include abdominal pain, allergy, diarrhea, headache, liver problems, nausea or vomiting, exacerbation of porphyries, pruritis, rash, somnolence, vertigo, or dizziness. In fact, in 2002, the World Health Organization recommended the use of Praziquantel in pregnant and lactating women, though controlled trials are still needed to verify this.

Another possible drug option is Tetrachloroethylene, a chlorinated hydrocarbon, but its use has been superseded by new antihelminthic drugs (like Praziquantel). A 1978 study also looked at the efficacy of several drugs on metagonimiasis infection, including bithionol, niclosamide, nicoflan, and Praziquantel. All drugs showed lower prevalence of eggs in feces, however only Praziquantel showed complete radical cure. Therefore, the authors concluded Praziquantel was the most highly effective, was very well tolerated, and was the most promising drug against metagonimiasis.

Evidence in support of the idea that helminthic infections reduce the severity of autoimmune diseases is primarily derived from animal models. Studies conducted on mice and rat models of colitis, muscular sclerosis, type 1 diabetes, and asthma have shown helminth-infected subjects to display protection from the disease. While helminths are often considered a homogenous group, considerable differences exist between species and the utilization of species in clinical research varies between human and animal trials. As such, caution must be exercised when interpreting the results from animal models.

Helminthic therapy is currently being studied as a treatment for several (non-viral) autoimmune diseases in humans including celiac disease, Crohn's disease, multiple sclerosis, ulcerative colitis, and atherosclerosis. It is currently unknown which clinical dose or species of helminth is the most effective method of treatment. Hookworms have been linked to reduced risk of developing asthma, while "Ascaris lumbricoides" (roundworm infection) was associated with an "increased" risk of asthma. Similarly, "Hymenolepis nana", "Trichoris trichiura", "Ascaris lumbricoides", "Strongyloides stercolaris", "Enterobius vermicularis", and "Trichuris suis" ova have all been found to lower the number of symptom exacerbations, reduce the number of symptom relapses, and decrease the number of new or enlarging brain lesions in patients with multiple sclerosis at doses ranging from 1,180 to 9,340 eggs per gram. However, "Ascaris lumbricoides", "Strongyloides stercolaris" and "Enterobius vermicularis" are not considered suitable for therapeutic use in humans because they do not meet the criteria for a therapeutic helminth.

"Trichuris suis" ova has been used in most cases to treat autoimmune disorders because it is thought to be non-pathogenic in humans and therefore has been rendered as safe.

The use of "Trichuris suis" ova has been granted by the USA Food and Drug Administration as an investigational medicinal product (IMP). While in the UK, the hookworm "Necator americanus" has been granted an IMP license by the Medicines and Healthcare Regulatory Authority. This hookworm is likely to be relatively safe, although it can cause temporary gastrointestinal side effects, especially following the initial inoculation and with larger doses.

The general ideal characteristics for a therapeutic helminth are as follows:

- Little or no pathogenic potential

- Does not multiply in the host

- Cannot be directly spread to close contacts

- Produces a self-limited colonization in humans

- Produces an asymptomatic colonization in humans

- Does not alter behaviour in patients with depressed immunity

- Is not affected by most commonly used medications

- Can be eradicated with an anti-helminthic drug

- Can be isolated free of other potential pathogens

- Can be isolated or produced in large numbers

- Can be made stable for transport and storage

- Easy to administer

Treatment for Eustrongylidosis is limited in the wading bird population due to the extensive amount of perforation in the stomach lining and limited funds available for treatment. In humans who are infected with Eustrongylidosis, surgery is required to remove the parasite from the intestinal wall. As surgery is not a feasible treatment option for wading fowl in the wild "en masse", treatment of the infected birds (a large portion of wild populations) has not been found, nor will likely be practical. There is the possibility that killing/removing the nematodes could do more harm to the host specimen than actual good.

Because they live so close to the outside of the body, "Thelazia" is one of the few nematode infections which can be treated topically.

Topical treatment of livestock, dogs and cats with organophosphates (such as ecothiopate iodide or isofluorophate) and systemic treatment with anthelmintics (such as ivermectin, levamisole, and doramectin) are recommended by the Merck Veterinary Manual. Other sources have reported positive results treating dogs with moxidectin, imidacloprid, or milbemycin oxime.

For the treatment of human cases, removal of the worm is suggested. Topical treatment with cocaine or thiabendazole have also been reported to kill the worms in human cases.

Because most, if not all, species of "Thelazia" are spread by flies, sanitary practices which reduce the presence of flies will also reduce the spread of thelaziasis.

Medication is the primary treatment for pinworm infection. They are so effective that many medical scientists regard hygienic measures as impractical. However, reinfection is frequent regardless of the medication used. Total elimination of the parasite in a household may require repeated doses of medication for up to a year or more. Because the drugs kill the adult pinworms, but not the eggs, the first retreatment is recommended in two weeks. Also, if one household member spreads the eggs to another, it will be a matter of two or three weeks before those eggs become adult worms and thus amenable to treatment. Asymptomatic infections, often in small children, can serve as reservoirs of infection, and therefore the entire household should be treated regardless of whether or not symptoms are present.

The benzimidazole compounds albendazole (brand names e.g., "Albenza", "Eskazole", "Zentel" and "Andazol") and mebendazole (brand names e.g., "Ovex", "Vermox", "Antiox" and "Pripsen") are the most effective. They work by inhibiting the microtubule function in the pinworm adults, causing glycogen depletion, thereby effectively starving the parasite. A single 100 milligram dose of mebendazole with one repetition after a week, is considered the safest, and is usually effective with cure rate of 96%. Mebendazole has no serious side effects, although abdominal pain and diarrhea have been reported. Pyrantel pamoate (also called pyrantel embonate, brand names e.g., "Reese's Pinworm Medicine", "Pin-X", "Combantrin", "Anthel", "Helmintox", and "Helmex") kills adult pinworms through neuromuscular blockade, and is considered as effective as the benzimidazole compounds and is used as a second-line medication. Other medications are piperazine, which causes flaccid paralysis in the adult pinworms, and pyrvinium pamoate (also called pyrvinium embonate), which works by inhibiting oxygen uptake of the adult pinworms. Pinworms located in the genitourinary system (in this case, female genital area) may require other drug treatments.

Anecdotal data gathered from helminth self-treaters and their physicians and presented in socio-medical studies suggest that a much larger number of diseases may be amenable to helminthic therapy than are currently being investigated by formal clinical trials.

Pinworm infection cannot be totally prevented under most circumstances. This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. Infection may occur in the highest strata of society, where hygiene and nutritional status are typically high. The stigma associated with pinworm infection is hence considered a possible over-emphasis. Counselling is sometimes needed for upset parents that have discovered their children are infected, as they may not realize how prevalent the infection is.

Preventative action revolves around personal hygiene and the cleanliness of the living quarters. The "rate" of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases.

The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after defecation and before meals. Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily. Simple laundering of clothes and linen disinfects them. Children should wear gloves while asleep, and the bedroom floor should be kept clean. Food should be covered to limit contamination with dust-borne parasite eggs. Household detergents have little effect on the viability of pinworm eggs, and cleaning the bathroom with a damp cloth moistened with an antibacterial agent or bleach will merely spread the still-viable eggs. Similarly, shaking clothes and bed linen will detach and spread the eggs.

One treatment for sparganosis is praziquantel, administered at a dose of 120 to 150 mg/kg body weight over 2 days; however, praziquantel has had limited success. In general, infestation by one or a few sparganum larvae is often best treated by surgical removal.

DNA analysis of rare worms removed surgically can provide genome information to identify and characterise each parasite; treatments for the more common tapeworms can be cross-checked to see whether they are also likely to be effective against the species in question.