This type of plant will cause a reaction whereas the ingredients interact with light. An animal ingesting such a plant is susceptible to sunburn, heat related illnesses, etc. Not all photosensitizing are considered extremely harmful, however, dependent upon climatic conditions/light, this class of plants can do great damage if the animal is not monitored.

• Buckwheat
• Goat Weed
• Klamath Weed
• Lantana
• Rape
• St. John's Wort