The phrase “cocktail safety” may sound like an oxymoron, or the punch line of a barroom joke. After all, we’re talking about alcohol, and a brandy Alexander is hardly as harmless as a smoothie.

But as modern bartenders dig into their cocktail chemistry sets for new techniques and arcane ingredients, Camper English, a drinks writer in San Francisco, decided it was time to create a website to head off potential disaster:

“Bartenders today are obsessed with experimentation, which I think is for the best,” Mr. English said. “But it’s often confusing as to what is safe and what is legal to use in beverages.”

There are a surprising number of cocktail components and procedures to be worried about. The website’s index lists more than 60, including fat-washing, in which a spirit is mixed with the oils of a solid, such as bacon or nuts, then frozen; the fat separates and is scraped away, leaving its flavor behind. “Botulism is a concern,” Mr. English said.

Older tiki mugs may have lead in the glaze. Moscow mule mugs can leach copper into a drink. Not all kinds of wood are safe for making barrel-aged cocktails. Homemade tonic syrups can cause cinchonism, a health condition related to ingesting too much quinine. (Symptoms include vertigo, muscle weakness and tinnitus.)

Some ingredients can trigger allergies. Others are not only potentially hazardous to use, but also banned by federal regulation, like tonka beans or calamus, an herb.

It’s enough to make you switch to beer.

The website is primarily intended for bartenders, who since the early days of the current cocktail revival have reached for unorthodox ingredients to bring new flavors — as well as public and media attention — to their drinks. This has often led to exciting and delicious drinks, but it can also be dangerous, because most bartenders may not fully understand the ingredients they’re using.

“They see other bartenders making homemade syrups and tobacco bitters, and make the assumption that that’s safe,” Mr. English said.

This isn’t the first generation of bartenders to take chances. Many pre-Prohibition cocktail books included recipes for homemade cordials and spirits that called for questionable ingredients like peach kernels, calamus root, ammonia and turpentine.