Review: Guava (from Arawak via Spanish, Guayaba) is a genus of about 100 species of tropical shrubs and small trees in the myrtle family Myrtaceae. Guavas are cultivated in many tropical and subtropical countries for their edible fruit. Red guavas can be used as the base of salted products such as sauces, constituting a substitute for tomatoes, especially for those who suffer from the latter's acidity.