In making barrel aged cocktails, wood/stave infusions, burning wood smoke, or any other use of wood in cocktails, bartenders should be aware that not all types of wood are safe for food use (including poisonwood, manchineel, and black walnut). Also woods that have been coated, protected, painted, or otherwise prepared as furniture, treated with insecticides, etc. should be avoided.
Most warnings against using woods in the medical literature come from lung health issues (Western red cedar, redwood, other logging woods) due to inhalation by woodworkers, so it’s hard to know if those irritations pass along to people drinking from vessels made from these woods.
It is best to only work with approved woods designated for food use.
See also Barrel Aged Cocktails.