Your condition and reaction after taking senna leaves are related to your physique, so you need to pay attention to personal conditioning and timely symptomatic treatment. & ltbr & gt& ltbr & gt Senna leaf is a laxative. Generally, diarrhea symptoms can appear after taking it for 4-8 hours, so pay attention to the dosage. Senna leaf is a Chinese herbal medicine for treating constipation.