Fruit tastes strange after I brush my teeth.

This is normal, so there is no need to worry. The surfactant (SLS) in toothpaste temporarily dulls the sweet receptors on your tongue while making bitterness more pronounced, which is why fruit or juice tastes bitter and astringent right after brushing. Taste usually returns within about 30 minutes to an hour, once saliva has washed the ingredient away. However, if altered taste continues for several days or your mouth also stings, there may be another cause, so it is worth having it examined.