The active ingredients in Vicks VapoRub work naturally through the inhalation of medicated vapors to relieve nasal congestion and coughing due to colds. Vicks VapoRub also relieves minor muscle aches and pains. Uniquely Safe: VapoRub is applied externally, so it doesn't interact with other medications the way pills can. Rubbing VapoRub on your chest or throat is not likely to cause drowsiness or jittery side effects the way some oral medications can.