The sticky white sap of milkweed is poisonous. Source: Emma Pelton/Xerces Society
Yes, I know you have read this in all sorts of blogs as well as in home remedy guides, but it’s very unwise to apply milkweed sap (Asclepias spp.) to rashes caused by poison ivy or oak (Toxicodendron radicans and related species). It’s claimed that the white, sticky milkweed sap reduces irritation and speeds up healing (although proof of such attributes seems entirely lacking), but applying milkweed sap to the skin is actually playing with fire!
The bright colors of the monarch butterfly caterpillar warn potential predators that it is poisonous. It gets its poison from the milkweed leaves it eats. Source: Judy Gallagher, Wikimedia Commons
True enough, milkweed can be a charming wildflower or garden flower and yes, it certainly does feed monarch butterflies (indeed, their caterpillars can eat nothing else), but the sap of milkweed is toxic. The toxicity does vary by species, but is nevertheless always present. In fact, it’s because their caterpillars eat the leaves of this poisonous plant that adult monarch butterflies (Danaus plexippus) become poisonous themselves, thus making them unpalatable to predators.
But Native Peoples Used to Eat Milkweed!
Yes, they did. Well, not all milkweeds: some are just too toxic for that! But least some species, like common milkweed (A. syriacus). However, if they were able to eat milkweed without suffering dire consequences, it’s because they cooked it first and the heat destroyed the sap’s toxic properties.
Sensitive Skin
Of course, milkweed sap itself is not always thought of as a contact poison: usually it’s ingesting it that causes a toxic reaction. However, some people have very sensitive skin and do react to simple sap-to-skin contact. Therefore, by applying milkweed sap to rashes caused by poison ivy, it can make the situation worse, causing an even more severe irritation.
Don’t Get Sap in Your Eyes
Getting milkweed sap into your eyes can cause severe irritation, much like that seen in this photo. Source: http://www.firmoo.com
But that’s not the main problem. The chief risk is that, by handling milkweed sap, you increase the risk of accidentally transferring it to your eyes afterwards. It only takes a tiny bit, much less than a drop, to cause severe irritation. Red eyes, tears and extreme pain are scary enough, but it’s blurry vision and blindness that send so many people to the hospital. The blindness is temporary and will clear up after two or three days, but it can be quite traumatic.
Take Precautions
Avoid handling milkweed if possible and when you have no choice, wear gloves, long sleeves and goggles or, at the very least, wash your hands and arms immediately afterwards. And never, ever brush a hand soiled with milkweed sap to your eyes!
The sap of jewelweed (Impatiens capensis) is safe to use and can be effective in reducing the irritation caused by poison ivy. Source: Fritz Geller-Grimm, Wikimedia Commons
So, what can you do about the dermatitis caused by poison ivy? First, wash immediately with soapy water, then consult a pharmacist for reliable medical treatment if that proves ineffective. If you prefer a natural remedy, try applying the sap of Cape jewelweed (Impatiens capensis), a common annual of North American forests and wetlands, to the rash. It has a reputation for relieving irritation, one that has been tested and confirmed effective … plus it isn’t toxic to humans!
