During the month of October reports of acorn poisoning have been widespread through Iowa and neighboring states. Representative animals from some herds were presented to the clinic. Other herds were described by practitioners in telephone conversations. When the first cases were encountered there was understandable hesitation in making the diagnosis since the problem was occurring on pastures that had been supporting trouble free grazing for years. As evidence continued to mount, however, it appeared that the heavy acorn production, together with abundant rainfall, may have resulted in an unusual problem this year.