It is permissible to warn people that a product is dangerous – that is, if the warning is truly warranted. Countless items are potentially dangerous if misused, and many processed foods are unhealthy if consumed in large quantities; in such cases, labeling the item “dangerous” is wrong. Labeling an item as unsafe is justified only if such a declaration is considered reasonable by normal standards. (See Day 43, condition 2.) Furthermore, if the information is not known firsthand, this must be mentioned when relating the information (see Day 43).
If the manufacturer is Jewish, he must be spoken to first (see Day 45). Failure to fulfill the above conditions would render the statement loshon horaas it would cause harm to the manufacturer, as well as to the consumer who will needlessly avoid the product.
