Over-the-counter antacids in tablet or liquid form can help cool the burn. Take a dose about every six hours as needed. Don't overdo it, though, because too much antacid can cause constipation or diarrhea. Even if you forget to take an antacid during the day, you should try to remember to take one at bedtime if you suffer from frequent heartburn. You need to protect your esophagus from the pooling of stomach acids that commonly occurs at night, when you are horizontal for hours on end. Heartburn that occurs during the night causes more damage than daytime heartburn.