PEOPLE who drink from backyard distilleries risk overdosing on alcohol or accidental poisoning from toxic byproducts, experts have warned.

A bad batch of home brewed Grappa that left one man in Ballandean dead, another on life support and two others fighting for their lives is thought to be the worst case of its kind in recent memory.

Professor Steve Allsop, director of the National Drug Research Institute, said too many things can go wrong when distilling alcohol in backyard setups.

``It does happen (people dying) from time to time in other countries, but this would be the first time I've heard of something on this scale,'' he said.

``It does suggest there is something quite toxic that they've ingested and it could be any number of byproducts.''

He said people making their own spirits were unable to determine the alcohol content of their brews - leaving them at risk of overdosing.

They also risk ingesting an accidental toxin created during the distilling process - such as methanol.

``The obvious message from this tragedy is that making your own spirits is a particularly risky process,'' Prof Allsop said.

He said Australians needed to take alcohol overdoses seriously rather than assuming people will ``sleep it off''.

``When people are so intoxicated they are passing out - they have overdosed.

``You actually need to get them help in the same way you would if they'd overdosed on any other drug.''

Curtin University Professor of Health Policy Mike Daube said most people distilled their own alcohol to make it stronger than what was sold in stores.

``You wonder why people are crazy enough to do this when you can get wine cheaper than bottled water,'' he said.

``The harms of alcohol are very well documented, but when you don't actually know what's in the product, when there's no quality control and it's likely horrendously impure, you're taking a very real risk.

``It's incredibly risky.''