Macadamia nuts may be delicious for people, but should not be shared with our fellow furry friends. Both processed and fresh forms can cause problems, with very little of the nut being eaten before issues are seen. The toxin in the macadamia nut is unknown, but often is related to stomach and brain issues. Clinical signs include vomiting, generalized tremoring of the muscles, weakness (especially seen in the back legs), difficulty walking, lethargy, pain in the stomach and joints, lameness, increased body temperature, and pale gums. These symptoms are usually seen about 12 hours after ingestion of the nut. These signs, though not ideal, often go away within 24-48 hours by themselves, but truly depend on how much your pet has ingested. Even though symptoms can resolve on their own, the severity of them can be decreased if veterinary care is provided.
It is extremely important to note, however, if the macadamia nut was eaten in something else (i.e. a cookie). While the macadamia nut itself may not cause long term issues, things like chocolate and caffeine (often found with these nuts) can.