[Tokolosh]

Each 5 mL (one teaspoonful), for oraladministration contains: Dextromethorphan hydrobromide 15 mg; promethazine hydrochloride 6.25 mg. Alcohol 7%.

Inactive Ingredients: Citric acid, corn syrup, FD& C Yellow #6, flavor, methylparaben, propylene glycol, propylparaben, purified water, saccharin sodium, sodium benzoate, sodium citrate.

Dextromethorphan hydrobromide is a salt of the methylether of the dextrorotatory isomer of levorphanol, a narcotic analgesic. It is chemically designated as 3-methoxy-1,7-methyl-9a,13a,14a-morphinan hydrobromide monohydrate.
Dextromethorphan hydrobromide occurs as white crystals sparingly soluble in water and freely soluble in alcohol. It has a molecular weight of 370.33, and a molecular formula of C18H25NO • HBr • H2O.
Promethazine is a racemic compound. Promethazine hydrochloride, a phenothiazine derivative, is chemically designated as (±)-10-[2-(Dimethyl-amino)propyl] phenothiazine monohydrochloride.

Forget about trying to make that at home.