The present case report documents acute ramson (Allium ursinum) toxicosis in tortoises. A group of four captive tortoises, including one Aldabra giant tortoise (Aldabrachelys gigantea) and three African spurred tortoises (Centrochelys sulcata), was fed a large quantity of ramson foliage. Approximately 12 hr later, the giant tortoise and two spurred tortoises developed acute and pronounced lethargy, anorexia, and palor of the oral and conjunctival mucosae. The remaining spurred tortoise showed palor of the oral mucosa but did not display other clinical signs. At initial presentation, approximately 24 hr after being fed with ramson, one spurred tortoise had died, and supportive care as well as the administration of activated charcoal was initiated in the remaining tortoises. While the giant tortoise died 5 days following initial presentation, the other two tortoises recovered. Gross pathological, histopathological, blood biochemistry, and hematological findings largely supported what has been documented in other species with Allium sp. toxicosis. Heinz bodies, however, do not seem to be a consistent finding in the blood of tortoises fed with ramson. Although the development of toxicosis due to the ingestion of ramson in tortoises seems to be dose dependent based on the present report, clinical practitioners and reptile pet owners should be aware of the potential detrimental effects of feeding this herb to tortoises. To the authors' knowledge, this is the first report of toxicosis caused by an Allium sp. in reptiles.