Blood pressure drops after taking a bath may be caused by vasodilation, sweating, change in body position and other factors. 1. Vasodilatation: per-pulse output has a certain effect on the level of blood pressure. When taking a bath, the temperature of the water may be higher than the body temperature, so that the peripheral vasculature undergoes diastole, which causes a reduction in the amount of return blood, thus leading to a decrease in per-pulse output and causing a decrease in blood pressure. Therefore, the blood pressure drops after taking a bath, may be caused by vasodilation. 2. Sweating: Sufficient blood filling is one of the conditions for the formation of blood pressure. If you sweat a lot after taking a bath, it may lead to a decrease in blood filling, which may lead to a decrease in blood pressure after taking a bath. 3. Change of body position: When taking a bath, the human body may be in a sitting position or semi-recumbent position, and after taking a bath, it may stand up suddenly. When you stand up suddenly, the blood output may decrease because of the decrease in the amount of blood returning to the heart, and the pressure on the arterial walls of the blood ejected from the heart with each beat decreases, which may lead to a drop in blood pressure after taking a bath. If your blood pressure drops after taking a bath, you should consult a doctor for 24-hour ambulatory blood pressure monitoring and other tests to determine the cause of the problem and follow the doctor’s instructions.