Yes, dogs can eat lettuce. It is generally safe and non-toxic for dogs to consume lettuce varieties such as romaine, iceberg, arugula, butterhead, green leaf, and red leaf lettuce. Lettuce is low in calories and mostly water, making it a light, crunchy treat that can support hydration and provide some fiber. However, lettuce should only be given in moderation and in small, bite- sized pieces to avoid digestive upset or choking. Feeding dogs large amounts of lettuce, especially iceberg with low nutritional value, may cause diarrhea or stomach issues. It is important not to feed dogs salad with dressings or toppings that may be toxic to them, like onions or grapes. Overall, plain lettuce can be a safe occasional snack for dogs, and some types offer vitamins A, C, and K that can benefit their health.