If you have a sink drain with a "J" where the trap is....it can settle there and eat away the pipe....ask me how I know!!
Haven't needed drain cleaner since I bought one of these.....you can't believe what it dredges up!! EWWW!! But your sink or tub drains fast after you clean the gook out of the pipe.
https://www.amazon.com/Turbo-Snake-Original-Pieces-Included/dp/B002JA5R7U

There are far less toxic methods...........and it can depend what is clogged and how much. Often, a plumber with a snake is best for a bath tub. Failing that? A plunger.....OR

Pour half a cup of baking soda down the drain, then half a cup of vinegar. Immediately plug up the drain with the rag, and allow the concoction to bubble and dissolve through the clog. After about an hour, pour down a pot of boiling water, followed by more hot water from the tap.

https://www.thespruce.com/how-to-unclog-a-drain-2718779

Drain cleaner is seriously harsh stuff. Do not use it if you are on a septic system. I've done the baking soda and vinegar thing, and it works well for minor draining problems, but for pipes clogged by trapped hair and stuff like that, DH will usually disconnect the S-trap and clean it out. A drain snake is your friend here. If those methods don't work, call a plumber.