When using prescription or over-the-counter eye drops, many people experience a bitter, nasty taste in their mouths. This side effect from the eye drops is caused by the solution working its way through your sinus passages and down the back of your throat. While there is not much you can do to avoid this, other than discontinuing use of the eye drops, there are measures you can take to diminish the effects.
Rinse your mouth with water.
Brush your tongue with a toothbrush, or use a tongue scraper. Because your taste buds are on the surface of your tongue, scrubbing away anything that is coating your tongue will improve the taste in your mouth.
Chew on a stick of gum. Citric acid is an ingredient in many chewing gums, and the acids in citrus can work as a palate cleanser.
Drink water frequently to flush out any remaining eye drop solution. Try a squeeze of lemon in your water or a sprig of mint, which is also an excellent palate cleanser.
Be vigilant with your oral hygiene during this time. Remove as much bacteria from your mouth as possible by brushing, flossing and rinsing daily.