Fourteen guinea pigs were given prednisolone daily for 20 days and 11 for 40 days. Another 20 formed the two control groups. Short-term prednisolone treatment significantly increased serum gastrin levels and antral G-cell population as compared to the control group. The same parameters significantly decreased following 40 days of prednisolone treatment as compared to the group of short-term prednisolone treatment. Forty days of prednisolone treatment significantly increased antral D-cell population as compared to the control and short-term prednisolone treatment groups. It is concluded that hypergastrinaemia and antral G-cell hyperplasia following corticosteroid administration is temporary and is accompanied by antral D-cell hyperplasia.