Drinking and eating is prohibited.

Didn’t you ask this before?

Yes, use the “is.”

Eating and drinking is considered as a unit.

However, most would post Something like : ”Eating or drinking on the patio is prohibited.”

Thanks, Punkey.

It’s more natural to say eating and drinking not drinking and eating.

A person who asks what kind of behavior is allowed in a shop or on a patio might be informed that eating and drinking are prohibited. This sounds natural (to me). What's the difference here?

That's what I would say too.

Are you talking to me or Punky? I just said eating and drinking sounds more natural than drinking and eating.

As you used the phrase eating and drinking not drinking and eatin* it would seem you agree with me.

As for the use or is or are, both are acceptable, as Punky has said eating and drinking are often classed as one experience so is can be used, as can are.

How about, consumption of food and drink is prohibited?

Neither of you directly...more of a general observation.

Yes, I think it sounds better.

That's fine, as consumption is what's being addressed.

I just had to make signs for my friend’s restaurant. They said:

The Patio and Bar are open.
Eating and Drinking is permitted on the boardwalk.

Fact and opinion is welcome.

Descriptivism and prescriptivism are rampant.