Bloke is drinking at a pub and after a few rounds goes to leave, explaining to the barman he has to go home to use toilet.

"Don't be stupid," says the barman, "We've got a perfectly good toilet here!" 

"Yes," explains the drinker, "but I take salts."

"So what? That doesn't matter - you can still use the toilet here!"

The drinker reluctantly agrees and heads for the toilet. 

After a few moments there is loud banging and the bloke emerges, followed by a foul smell. 

The barman races into the toilet where he sees crap all over the ceiling and walls. He races back into the bar. 

"What the hell went on in there?!" he demands.

"I told you," explained the drinker.

"No, you said that you take salts!" yelled the barman.

"That's right," the drinker shrugs, "somersaults."