After my earlier post on the perils of poison ivy in the winter, here is a slightly less fraught tale of garden chemical hazards. Listing the most common complaints of the outdoors in summer in North Carolina, the fig would be low on most lists. Mosquitoes, snakes, spiders, the heat, the rampant weeds, all of these would rank ahead. But after doing some work in the garden last week, I came back inside and found my eye sore to the touch. I figured the culprit to be one of those all too common weeds, but my horticulturist wife saw it differently (and she knows her poison ivy!). Because among the work I had been doing out there was the arduous task of sampling the fruits of our splendid fig tree. When she pointed this out, I recalled taking the fruit and some white sap running down my fingers. All it took from there was for me to wipe at my eye, for fig sap is a known irritant.
Fortunately, it is relatively mild and some aloe and a day or two and all was well. No doctor visit for steroids required. But I was curious about the irritant in fig sap so I did a little digging.
One thing I found was about the photoactive ingredients of the sap, psoralen and bergapten, present in the sap but not the fruit.
These compounds increase your sensitivity to light and have been used as tanning activators, though that comes with a higher risk for skin cancer. Seems like a rough trade-off.
In addition to those furocoumarins, there are also some triterpenoids. A paper on PubMed talks about them. They note that “calotropenyl acetate, methyl maslinate and lupeol acetate showed potent and persistent irritant effects”. Just to show how complex this gets, lupeol is listed as an anti-inflammatory.
Though it just affected the membranes around my eyes, it can get much worse if you are allergic or sensitive to the sap or of course if you work with it. Such complaints are common among pickers and handlers. Fig latex (i.e. the milky sap) has been used in medicinal preparations for skin complaints and was also an ingredient in a household detergent in central America until too many complaints of reactions led to its withdrawal.
It just goes to show it is hard to know where you might be safe out in the garden. Best to run back inside, wash your hands and enjoys the figs.