Sweet marjoram is distinguished from Oregano which sometimes referred to as wild marjoram. 

Ibn Qayyim in "Medicine of the Prophet" said, "When its aroma is smelled, it relieves cold  headache caused by phlegm, colds, black bile and thick flatulence pressure. It relieves congestion, and clogs in the nose and head and dissipates most cold, wet swellings … Marjoram ointment helps relieve backache, knee pain and fatigue.”

Listed in food qualities as hot and dry.

In TCM Marjoram is called Mo Jiao Lan and is considered sweet, cool, pungent and slightly bitter.