People are stealing hand sanitiser from Waikato Hospital to get an alcohol fix with numerous reports of theft in the last three years.
However, drinking a hand sanitiser such as Sterigel which contains alcohol can cause aggressive behaviour, a night shelter manager told RNZ.
The Waikato DHB reported numerous cases of Sterigel being stolen in the past three years.
Hamilton Christian Night Shelter manager Peter Humphreys said homeless people, among others, had been using it as a way get alcohol for the past decade.
It could cause serious behaviour changes, he said.
"Some of them get quite aggressive with this stuff . . . because it's a chemical concoction, you don't know what's actually in it - it's not like a bottle of wine or whatever."