Are celery leaves poisonous?

QUESTION: Are celery leaves poisonous? Do I need to keep my dogs away from my celery plants? -Frank C.

ANSWER: Celery leaves are not poisonous, but edible and nutritious in small amounts. If you were to eat multiple pounds of celery leaves every day, you might be affected by the toxic compounds that exist within the plant in minuscule amounts. We’ll get back to that in just a sec. First, let’s discuss why you should always wash your hands after handling celery, and thoroughly wash any part of your skin that comes into contact with celery juice before going outdoors.

It’s a little known fact that celery juice can be dangerous to your skin, but if you get celery juice on your skin and then venture out into the sun, you will likely develop a rash within 12 to 36 hours. This is because celery, like many other plants, contains the compound Psoralens, which increases your skin’s sensitivity to ultraviolet light. Typically, the rash lasts for five days, but leaves the skin hyperpigmented for months, and the burning-like pain that accompanies the rash can linger as well, where the skin rash and discoloration take place. So, avoid celery-induced skin irritation by always washing your hands and arms after handling celery in the kitchen. If you spill celery juice on your skin, be sure to wash the area well before exposing yourself to the sun.

Now, back to the danger of celery leaf consumption. Celery, like many other natural foods, has toxic elements. Technically, celery leaves, when consumed in extremely large amounts, can have toxic effects. Toxic elements exist in many natural foods, but in such small amounts that you would have to eat excessive amounts of one particular food over a long period of time before it would become dangerous. According to the National Academy of Sciences, from their book Toxicants Occurring Naturally in Foods, “If one’s diet contains a reasonable diversity of foods and no extraordinary amount of any specific food, then no single chemical is likely to be consumed in (a) toxic amount.”

With this being said, eating very large amounts of raw celery can cause thyroid problems. Goitrogens are substances that interfere with the uptake of iodine in the thyroid and uncooked celery can act as a goitrogen if consumed in high enough amounts, and can cause goiter, or enlargement of the thyroid. Goiters can cause neck swelling, difficulty breathing and swallowing, and can lead to hypothyroidism, causing weight gain, lethargy, dull, dry skin, and fatigue. Alternatively, goiters can become toxic and produce excess amounts of the thyroid hormone, leading to hyperthyroidism. Cooking celery destroys most goitrogens, and eating a diverse diet with no excessive amounts of any particular food, will keep your body from building up any toxins that occur in natural foods in small amounts. So, feel free to eat celery, and celery leaves, in reasonable amounts, raw or cooked. Just don’t start eating nothing but celery, or start chomping through multiple pounds of it per day, and you should be just fine.

Are celery leaves poisonous to dogs?

No, celery, and celery leaves are perfectly safe for dogs, and are actually recommended as healthy weight-loss treats for your dogs, if you can get them to eat it.