Propolis, which is collected from plant stalks, leaves, and buds by the worker bees, is a natural product with high antioxidant features. Besides, it exhibits potent antibacterial activity. Research conducted at Babol University in 2013 compared the antibacterial activities of three different propolis extracts (alcohol concentrations: 0, 15, 40%) and aloe vera gel on E. faecalis using three different methods involving disk diffusion, microdilution, and direct contact test. The study results demonstrated the highest efficacy of alcohol extracts (15% and 40%) through direct contact on bacteria. Hence, I advise applying at least 10% alcohol extract of propolis directly on the skin or consuming it by mixing your favorite drink or food. For example, propolis extract acts as an antibacterial agent when applied onto the acne or dark spots on the skin. I recommend consuming at least 20 drops for adults or ten drops for children every day.
Reference: Ehsani, Maryam, et al. "A comparison between antibacterial activity of propolis and aloe vera on Enterococcus faecalis (an in vitro study)." International Journal of Molecular and Cellular Medicine 2, 3 (2013): 110.