Carrots are rich in carotenes, which are substances related to vitamin A. They're found in the orange pigments and are good for you, but, if you eat lots and lots of carrots, you can develop a yellowish or orange cast to your skin. It's mostly noticeable on the soles of your feet and the palms of your hands.
Benadryl is another decongestant safe for use in cats, although it is usually not as effective as chlortrimeton in treating congestion. Benadryl is generally more beneficial with treating snake bites, reactions to vaccinations, itching, and insect bites.
Cats can suffer from bacterial infections and viral infections that cause congestion in the sinuses. This can cause pain and discomfort for the cat and because they cannot simply blow their nose, cats may need some help in the form of a decongestant. There are a few different decongestant options to choose from, with some cats responding better to some than others.