Can a Cat Eat Too Much Brewer's Yeast?

Too much yeast for any living being is not a good thing. For a kitty babe of his size he should not have more than 1 teaspoon of it a day 'or' the pills (not both) but the pills must be regulated via package instructions.

I like mrs.story's idea about using child guards on a cabinet or maybe even keep the yeast in an airtight container in the refrigerator. It's possible your kitty is not getting enough balanced nutrients in his food and that's why he is seeking out the yeast.

I don't know if he can overdose, but you should probably find a new place to keep the can.

One of my cats is very clever (and determined). He used to open the desk drawer where I kept his emu jerky bits. I'd come home and find the drawer half-opened, the bag on the floor, shredded and all the jerky gone. So I put it into the heavy file drawer beneath. He figured out he could pull open the lighter drawer above the file drawer, reach under the lighter drawer and into the closed bottom drawer. I'd still come home to the empty, shredded bag in the middle of the floor. So I had to stop keeping the emu in the desk, and move it to a sturdier container in a different part of the house.

We have hooks on some of our kitchen cabinets (for child-proofing). Before we put those in, he'd open the cabinet and knock his canned cat food on the floor. He can still pull on the doors, but they only open about an inch, so he can't get anything out. You might need to do something like this, so your cat doesn't get himself into any trouble.