Species

Drugs named most often, by active ingredient

Ordered by report count, which follows how widely a drug is used. FDA states that these data "cannot be used to estimate the risk associated with the product or compare one drug or device product with another". openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand.

Signs listed in reports

share of sheep reports listing the termall species

1. Death55%589
2. Depression[dull, quiet or withdrawn]6.2%66
3. Recumbency[lying down and unable or unwilling to rise]5.8%62
4. Anorexia[not eating]5.6%60
5. Ataxia[unsteady, uncoordinated movement]5.2%56
6. No sign[no clinical sign was reported]4.7%50
7. Accidental exposure[exposure that was not intended]4.3%46
8. Diarrhoea[diarrhea]4.2%45
9. Ineffective, worms NOS[legacy FDA term: the product did not have the expected effect (worms nos)]4.2%45
10. Hypersalivation[drooling]3.8%41
11. Lack of efficacy - NOS[the product did not have the expected effect]3.6%39
12. Ineffective, parasite(s) NOS[legacy FDA term: the product did not have the expected effect (parasite(s) nos)]3.6%38
13. Abortion3%32
14. PR-lung(s), lesion(s)[legacy FDA term: lesions found in the lungs]3%32
15. Anaphylaxis[sudden severe allergic-type reaction]2.9%31
16. Dyspnoea[difficulty breathing]2.9%31
17. Death by euthanasia[the animal was euthanized]2.5%27
18. Collapse2.4%26
19. Lack of efficacy (endoparasite) - tapeworm[the product did not have the expected effect: tapeworms]2.3%25
20. Ineffective, stomach worm NOS[legacy FDA term: the product did not have the expected effect (stomach worm nos)]2.1%22
21. Weakness2.1%22
22. Anaemia NOS[low red blood cell count]2%21
23. Inappropriate preparation of medication1.9%20
24. Lack of efficacy (endoparasite) - roundworm NOS[the product did not have the expected effect: roundworms]1.9%20
25. PR-heart, lesion(s)[legacy FDA term: lesions found in the heart]1.9%20
26. Trembling1.8%19
27. Ineffective, strongyles[legacy FDA term: the product did not have the expected effect (strongyles)]1.7%18
28. Fever1.6%17
29. PR-liver, lesion(s)[legacy FDA term: lesions found in the liver]1.6%17
30. Staggering1.5%16

Single ingredients, pooled across combinations

• Ivermectin250 reports · 23.4%
• Albendazole144 reports · 13.5%
• Tilmicosin Phosphate118 reports · 11%
• Monensin108 reports · 10.1%
• Moxidectin57 reports · 5.3%
• Vitamin E36 reports · 3.4%
• Levamisole Hydrochloride34 reports · 3.2%
• Doramectin32 reports · 3%
• Progesterone29 reports · 2.7%
• Tulathromycin22 reports · 2.1%
• Florfenicol20 reports · 1.9%
• Oxytetracycline17 reports · 1.6%
• Flunixin Meglumine14 reports · 1.3%
• Fenbendazole13 reports · 1.2%
• Penicillin G Procaine11 reports · 1%
• Clorsulon10 reports · 0.9%

Age and weight

Outcomes and report types

Coloured bar: sheep reports. Grey bar: all 1,357,245 reports. Outcomes are as stated by the reporter.

Trend

Reports by month FDA received them. The newest months are incomplete because FDA posts reports with a delay of three to six months.

Where this comes from. Counts are built from the openFDA Animal & Veterinary adverse event bulk files released 28 Sep 2026, which hold reports FDA's Center for Veterinary Medicine received through 31 Mar 2026. openFDA masks brand and manufacturer names in these files, so drugs are counted by the active ingredients each record discloses and no figure is attributed to a brand, application or company. Ingredient names, and the separate reference lists of approved products, follow the FDA Green Book as of 1 Oct 2026. No report text, lot numbers or reporter details are published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.