Emerging investigations indicate extracts from Psidium guajava leaves exhibit potent anti-cancer effects against numerous human cancer cell lines spanning lung, breast, prostate, liver, colon, ovarian, cervical, gastric, and skin cancers. [1?"3]. Bioassays demonstrate guava leaf extracts suppress cancer cell proliferation, induce apoptosis, and inhibit tumor metastasis and angiogenesis pathways. [1, 4] Several bioactive phytochemicals have been isolated and contribute specific anti-cancer actions [4]. As guava plants grow abundantly across tropical and subtropical climates in Asia, Africa, and South America, continued research into traditional guava leaf preparations as an economical complementary medicine for cancer is compelling [3, 5]. Guajadial, a meroterpenoid enriched from guava leaf oil, significantly inhibits nonsmall cell lung cancer cells. Both in vitro and mouse model experiments demonstrate suppressed proliferation and migration of A549 and H1650 cells [2]. An associate