This chili is presumed to be the mother of most domestic chilis, at least those that are in the species Capsicum annuum. It has been used for a long time as flavoring and food preservative. The heat (measured in Scoville heat units—SHU) of this chili ranges from 50,000 to 100,000 Soville units. The variability comes from conditions the plant grew in, and soil.

The name, chiltepin, is a combination of chili and tepín—tepín is derived from a Nahuatl word meaning "flea" thus, “flea chili”. Some regions have a similar-sized pepper, 'Pequin' (also called 'piquin') which is often confused with tepin, although the tepin fruit is round to oval where as the pequin's fruit is oval with a point, and the leaves, stems and plant structures are very different on each plant. In many regions this plant is called “bird pepper” because it is spread by birds. The etymology of the word Capsicum, either from the Greek word δάγκωμα (= to bite), on account of the burning strength of the seeds or from the Latin voice capsa (= box), on account of the boxy shape of the cultivated fruits. The species name, annuum, is a misnomer—many people in colder climates assume chili plants are annuals but they are, indeed, perennial. The variety, glabriusculum, is Latin for glabrous, without hairs, –ius, characteristic of, and –culum, the diminutive: somewhat glabrous.

There are 43 species of Capsicum native to the Americas (and now introduced in tropical and subtropical climates around the world) and some Pacific islands. There are 5 species that are commonly grown as crops: Capsicum annuum, C. chinense (though named as if native to China, this is a misnomer), C. pubescens, C. baccatum, and C. frutescens.

There isn’t always consensus about the difference between chiltepín and pequin, but sometimes the different drying methods used for the chiltepín or tepín and 'Pequin', can help tell these peppers apart. Tepins are always sun-dried, whereas the Pequins are commonly dried over wood smoke, and the smell of the smoke in the Pequins can help separate the two varieties. Pequins are not as hot as chiltepins (only about 30,000–50,000 Scoville units), but they have a much slower and longer-lasting effect. Both peppers are also sometimes picked green and pickled.

Chiltepin plants are readily available in the trade, and we recommend in Arizona to leave the wild plants alone, as they are endangered by enthusiastic wild-harvesting, ranching, and development. They are increasingly rare in Arizona. In Sonora, where these plants are much more common, there is a seemingly sustainable industry harvesting wild chiltepin.