The llama (Lama glama) presents today's veterinarian with all the difficulties and medical uncertainties of treating a new species. Both the rapid increase in their numbers in the United States, and their relatively high monetary values have contributed to their recent significance in veterinary medicine. Complexities encountered by the veterinarian begin with llama anatomy and physiology, both of which are somewhat different 'from what is seen in common domestic species such as the equine, bovine, or ovine. Thus, it is not surprising that some llama diseases present uniquely and are poorly understood and researched at this time. An important condition which belongs in this category is the failure to thrive syndrome of llamas (FTS).