Miracle berries - or their more commonly found counterparts, Mberry tablets - alter your sense of taste and make sour and bitter foods taste sweet! They're a naturally occurring berry that contains an active protein - dubbed "miraculen" by the ever-original scientist team that discovered it - which binds to your tastebuds an inhibits them from firing sour signals, causing the sweet signals to be stimulated instead. The capsules themselves contain nothing but the berry and some cornstarch, to make them stick.

I tried them with a friend, and we found that they did cause tart fruits, like lemons and limes, to taste sweet, as well as enhanced the sweetness of fruits like strawberries, oranges and apples. They worked to make vinegar bearable as well, though it still wasn't exactly delicious (apple cider vinegar, as my friend found out, did not work for some reason). It was a really neat experience, and I'd love to host a flavor party some day!