Yes! It dries out your colon and makes you more susceptible to micro-tears in your anal walls and makes it more likely that you’ll get constipated. There’s also a small but real chance that you could get a perforated bowel which is a medical emergency. It also washes away a natural layer of mucus in there which, while gross, is necessary.
Doing it once in a long while is probably fine but it’s not necessary unless you’re doing something super intense that goes up into your colon and you’re not willing to clean up afterwards.
If you absolutely must, use clean douching equipment and lukewarm water with a teaspoon of salt per cup of water dissolved in it. The salt mixed in will keep the water from dehydrating you because yeah, that’s another risk of douching. Your body has a very specific balance of salt it wants and plain water will sap away some of that.
Also remember to use lube, kids! It reduces your risk of getting an STD or a minor injury!