Samples of Nzu found in African specialty stores in Texas were shown in DSHS lab analysis to contain high levels of levels of lead and arsenic—both extremely toxic, especially to developing children.
Consumers, particularly pregnant and breastfeeding women, are advised to completely avoid Nzu, which is commonly sold in clay-like balls in African specialty stores under the names Calabash clay, Calabar stone, Mabele, Argile, La Craie, and Salted Nzu.
The FDA also recommends that anyone who has been using this product see a health care professional right away.
Any adverse events that may be related to use should be reported to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program online [at www.fda.gov/MedWatch/report.htm], by phone 1-800-332-1088, or by returning the postage-paid FDA form 3500 [which may be downloaded from the MedWatch "Download Forms" page] by mail [to address on the pre-addressed form] or fax [1-800-FDA-0178]. –FDA