In a collaborative study with small-animal veterinary surgeons, dogs with fur and skin conditions were treated with biotin (approximately 5 mg biotin/10 kg body weight/day) for 3 to 5 weeks. In total 119 cases could be treated which were reported to show symptoms such as dull coat, brittle hair, loss of hair, scaly skin, pruritus or dermatitis. Cases requiring other treatments with e.g. glucocorticoids, were excluded from the study. In 60% of the cases all symptoms were reported to be cured after the biotin treatment and in a further 31% an improvement was noted; in only 9% no effect was recorded. All breeds responded but to a variable extent: e.g. in Poodles the response was lower (no response in 6 out of 11 cases) than in Alsatians where all improved and 14 out of 29 were completely cured. The results confirm the favourable effect of biotin for treatment of fur and skin conditions in dogs.