The Medicinal Plant Garden

of Birmingham-Southern College

  • Baptisia australis
  • Baptisia australis

Common Name

Blue False Indigo, wild indigo, baptisia, rattlepod, rattlebush

Related Species

Baptisia australis var. australis, Baptisia australis var. minor, Baptisia australis var. aberrans, Baptisia trincota

Geographic Distribution and Habitat

B. australis can be found as far west as Texas and Nebraska to eastern seaboard states. New Hampshire is the furthest northeast it occurs as native, while it still extends halfway through Canada. The plant prefers sunny areas and along tree lines. It prefers well-drained, loamy soils or gravelly or sandy soil (USDA)


B. australis is perennial and leguminous. Its growth habit is a forb or herb. It’s flowers are axillary and with an erect short terminal raceme. At is biggest it can be 5’ tall and 3’ wide, but is usually closer to 3’ tall, 2’ wide. The flowers are anywhere from light blue to purple and they are hermaphroditic. Its fruit is a pod containing a few loose seeds (USDA, Foster, 2000).

Portion of the Plant Used

The root is used but the seeds can be considered toxic (Foster et al., 2000).  It produces by seeds or rhizomes (USDA).

Traditional Uses

The root of B. australis had many uses by Native Americans. The tea was used to induce vomiting, however cold tea was used to stop vomiting. It was placed in the mouth to treat toothaches. An anti-inflammatory poultice was used for as an anti-inflammatory. It can be a substitute of B. tinctoria, which is native to a slightly more northern range of the United States than B. australis.


There is little current research on B. australis or its active ingredients. B. tinctoria, the northern relative of B. australis, in combination with other herbal medicines significantly reduced the severity of cold symptoms and duration compared to placebo (Naser et al., 2005; Roxas and Jurenka, 2007). B. tinctoria is also reported to be an immunostimulant (Classen et al., 2005; Banerji et al., 2012). Extracts of B. tinctoria, again in combination, were also shown to have a positive effect on the course of influenza A infection in mice (Bodinet et al., 2002).

According to the PDR for Herbal Medicines, B. tinctoria the northern relative of B. australis, is very good at stimulating the immune system. Human erythrocytes are positively affected by the ethanol extract of the Baptisia genus. There are indications to that it can help infections upper respiratory tract infections, mucus membrane inflammation, and other internal inflammations. Taking water that has been soaked in the root can be used to clean open and inflamed wounds.

The relative of B. australis, B. tinctoria, was also proven to increase efficacy against influenza A infection in mice, which supports the past theories that Baptisa plants can boost immune function. (Ramussen, 2009; USDA, Foster et al. 2000). Many in holistic medicine believe these immunostimulant effects can help prevent cancers (Yarnell, 2008).

Side Effects, Interactions, and Contraindications

A low doses of saponins causes the secretolytic effect, while vomiting is induced at the higher dosage. No specifications were given (van Wyk, 2004).