2-Hydroxycinnamic acid-d4 is deuterium labeled 2-Hydroxycinnamic acid. 2-Hydroxycinnamic acid is a phenolic acid with antimicrobial and antioxidant properties. 2-Hydroxycinnamic acid has antimicrobial activity against Staphylococcus aureus and is not susceptible to drug resistance. 2-Hydroxycinnamic acid shows inhibitory effects on infection of HIV/SARS-CoV S pseudovirus with an IC50 of 0.3 mM. In addition, 2-Hydroxycinnamic acid has neuroprotective and antitumor activity[1][2][3][4][5].