Dogs should not have lemons. Lemons contain toxic compounds for dogs, such as citric acid, limonene, linalool, and psoralens, which can cause stomach upset, vomiting, diarrhea, drooling, and even more serious issues like liver damage or central nervous depression if consumed in larger amounts. The lemon peel and rind pose additional risks of toxicity and choking or intestinal blockage. Most dogs instinctively avoid lemons because of their sour taste and strong smell, but even small accidental ingestion can irritate a dog's digestive system and cause discomfort.