Total fasting and thirsting of piglets for 48 h produced a decrease in the ascorbic acid (AA) content of the liver, while the blood plasma AA levels remained unchanged or were increased. The changes were more marked in piglets less than 1 week old than in piglets aged 6–7 weeks. Administration of glucose to newborn fasted piglets restricted the decrease in AA levels in the liver. Administration of ACTH to conventionally fed piglets produced no adverse effects on their AA metabolism. It is concluded that the level of glucose is an important positive factor determining the degree of endogenous synthesis of AA. Possible effects of stress are discusse