The US Food and Drug Administration issued a public warning about a hazardous substance discovered in certain homeopathic teething tablets.

"The agency is warning consumers that homeopathic teething tablets containing belladonna pose an unnecessary risk to infants and children and urges consumers not to use these products," the warning statement issued by the FDA last Friday (Jan. 27) read.

Experts found inconsistent levels of belladonna on the products that are "sometimes far exceeding the amount claimed." Belladonna, which means "beautiful lady," comes from the deadly nightshade plant that is known to be toxic.

According to Fox 31, the agency has been monitoring reports of adverse effects since 2010, after a lab discovered the inconsistency of the belladonna levels on Hyland's Teething Tablets. The company has since recalled its products and changed its production process to address the inconsistency problem.

But with the recent discovery, FDA said it had already communicated with Standard Homeopathic Company, owner of Hyland's homeopathic teething products. However, the company refused to call back its items off the market.

The FDA is asking consumers to stop and immediately dispose products manufactured by Hyland and seek for safer alternatives.

"The body's response to belladonna in children under two years of age is unpredictable and puts them at unnecessary risk," Janet Woodcock, FDA's Center for Drug Evaluation and Research director, said.

She further added that parents should immediately seek their doctors' attention if symptoms including agitation, breathing difficulties, constipation, excessive sleepiness, lethargy, muscle weakness, skin flushing, seizure, and urination difficulties are being manifested by their child after use of homeopathic teething products.

This is, however, not the first instance the FDA had push to recall homeopathic teething products. Last November, Raritan Pharmaceutical of East Brunswick had to call back three products containing belladonna, and two of which are marketed by CVS, the Forbes reported. Last September, it also warned against use of homeopathic teething tablets and gels.