Indian Lettuce (Lactuca indica L.) is a valuable medicinal herb but there are still no many researches about this plant. In this work, the physiological responses of Indian lettuce plants under water deficit conditions (5, 8, and 11 days of water stress) were investigated. The Indian lettuce wilted after 5 days of water stress (66.66%), the wilting rate increased after 8 (93.33%) and 11 days (100%) of water stress. The longer duration of water deficit stress caused the slower recovery of plants after rewatering. The water deficit stress caused a decrease in chlorophyll fluorescence, non-associated water content as well as flower formation of Indian lettuce. But the water deficit stress increases the associated water content and the flowering time of this plant.