My boyfriend is on blood thinner medication - Warafrin (?). Can he take TheraFlu for chest cold/mucus relief? (Powder that dissolves in hot water.)

Following is a system that allows you to enter each drug by name and be provided with a printout of any possible interactions.

Drug Interactions Checker | Drugs.com

According to my Epocrates drug interaction checker he can take both of those medications without interaction.