The optimal time to take antihypertensive medication depends on the patient’s daily level of blood pressure fluctuations, clinical symptoms, and co-morbid underlying conditions. In a normal person, blood pressure has two peaks and one trough during the day. Blood pressure is high during the day and low at night. Blood pressure begins to rise between 4 and 5 a.m., with a peak beginning around 6 and 8 a.m., and then gradually plateaus. It peaks again from 4 to 6 p.m. and then slowly declines. A trough is reached at 2-3 am and is maintained until 4-5 am. Therefore, for hypertensive patients who still exhibit normal blood pressure peaks and valleys, medications can be taken to control these two blood pressure peaks. Since the highest daily blood pressure levels are generally between 8-10 am and 4-6 pm, the best time to take antihypertensive medication for hypertensive patients is early in the morning on an empty stomach to effectively control daily blood pressure levels. In the case of oral long-acting antihypertensive drugs, the time to take antihypertensive drugs is generally early in the morning. If taken twice a day, the first dose should be taken within half an hour after waking up in the morning, and the second dose should be taken between 4 and 6 pm. If the blood pressure has lost these two normal peak performances. 24-hour ambulatory blood pressure measurement should be perfected first to find the time when blood pressure is highest and apply medication to control it earlier before it rises. If patients present with high nighttime blood pressure or early morning blood pressure peaks, such patients may consider taking antihypertensive medications before sleep to effectively control nighttime and early morning blood pressure levels.