Pepper is considered to be a highly alkaline food, which means that it is not acidic in the least. Those who have problems with acid reflux will find that it is extremely important to eat mostly alkaline foods so it does not irritate this issue even more.
Some of the foods that you will want to avoid because they are considered to be extremely acidic include lemons, oranges, and grapefruit. All of these foods can contribute to problems with heartburn/acid reflux. Most types of pepper are very alkaline though, so even if you typically have problems with heartburn you shouldn’t have any issues.