Its medical. There is usually some kind of mint oil in vapor rub. When inhaled, it breaks up phlegm and opens airways. It also lowers inflammation so your nose, throat, chest, etc. are more comfortable.
Most vapor rubs contain menthol. The smell may unblock your sinuses for awhile to make breathing easier. The menthol makes you feel kind of cool and refreshed. However, there is nothing in these rubs to take the sickness away.