Euphorbia fischeriana is a member of the Euphorbia genus, which means that it produces a milky sap that is moderately harmful to touch and ingest. When direct contact is made between bare skin and this sap, you will likely experience irritation and potentially blistering. When the sap has touched any mucous membranes, such as the eyes, nose, or mouth, this is when the symptoms become more serious, causing extreme inflammation, and potentially Keratouveitis, a condition that impacts your ability to see. It's therefore recommended to wear protective equipment when handling euphorbia fischeriana and to keep out of reach of children. Because of its irritant effects, it may cause swelling of the lips, tongue, and throat if ingested.