There are two varieties of this spice. Large or big and a small pod variety—green cardamom. Big cardamom is also called black cardamom, Bengal cardamom, or Siamese cardamom and belongs to the Amomum genus. The smaller variety is from the Elettaria genus. Both Amomum and Elettaria genus belongs to the same Zingiberaceae family.
The spice is rich in medicinal properties, and tea infused with cardamom will be beneficial.
Let me now briefly summarize some evidence-based information on cardamom’s medicinal properties.
Small cardamom (Elleteria sps) was observed to reduce blood pressure in stage 1 hypertensive individuals. It also helps reduce the tendency of blood clot formation and raise the antioxidant levels in the body (Verma et al. l, 2009). The extract inhibited human platelet aggregation (Suneetha et al., 2005). Verma et al. (2010) found Amomum subulatum to be a cardio-adaptogen against physical stress.
It is a diuretic with sedative action (Gilani et al., 2008). They believe that the ability to lower blood pressure is due to the diuretic and sedative properties of the species. The antioxidant effect of the bark and black cardamom seed was also observed in an experiment conducted on rats fed on a high-fat diet (Dhuley, 1999). The antioxidant property of cardamom was observed to vary with variety (Amma et al., 2010).
The anti-convulsant and sedative properties of an Ayurvedic formulation Unmadnashak Ghrita which has Elletaria cardamomum, Gardenia gummifera, Ferula narthex, Bacopa monneri, and cow’s clarified butter observed in an experiment conducted on mice (Achliya et al., 2004).
The anti-microbial action of its oil against one or more bacterial species was observed in studies (Kubo et al., 1991; Supriya et al., 2012; and Kumar et al., 2010). The antibacterial action of the dry cardamom fruit extract was observed in various other studies also (Kaushik et al., 2010; Jazila et al., 2007; and Hussain et al., 2011). The anti-microbial activity of both large and small plants was observed against microorganisms causing dental caries (Aneja et al., 2011). Cold extracts of Amomum subulatum were effective against Pseudomonas aeruginosa, a hospital-infection-causing organism (Jain et al., 1976).
You can pick from the books here to learn more about herbs and spices and their medicinal and other properties.