Strawberries along with peaches, oranges, grapes, and raspberries are likely to worsen heartburn in someone who already has this problem.
If you want to reduce the risk of worsening your heartburn, you will definitely need to know which foods to avoid and which to get plenty of in your everyday diet.
You will want to avoid any fruits which are considered to be acidic, such as strawberries. Their acid content is such to where you will want to steer clear of them as much as possible if you have heartburn. Although this does not mean you can never have them, you will want to limit your intake as much as possible.