Dear Cecil: Various health and yoga websites claim that iceberg lettuce contains chemicals similar to laudanum, morphine, or other opiates. There are also reports of people being admitted to hospitals after injecting themselves with lettuce extracts, and papers about smoking lettuce. I have found no information about the chemical constitution of lettuce that mentions morphine or opiates. Are there such things in supermarket lettuce? Curious Lettuce Eater, via e-mail

Cecil replies:

You’re thinking: How can iceberg lettuce be a drug? It barely qualifies as a food. Little do you know. While the stuff from the supermarket isn’t likely to do much, lettuce generally speaking does contain psychoactive compounds. Enough to get you high? Hard to say. Judging from available evidence, the stuff might do nothing, give you a buzz, or kill you. Here’s what we know:

1. When cut, the stems of lettuce plants ooze a milky juice whose appearance, taste, and smell are said to be similar to opium. Once dried, the substance is called lactucarium, or lettuce opium. Used by the ancient Egyptians, the stuff was listed in the Pharmacopeia of the United States of America as late as 1916. It can still be found in herbals and such, which describe it as a sedative and cough suppressant. Lettuce opium can be found in all lettuce species but is most commonly extracted from wild lettuce, Lactuca virosa.

2. Most of what little research has been done on the pharmaceutical effects of lettuce is old — one article in my stack was published in 1904. A 1940 study found that fresh lettuce juice indeed contains two sedatives, lactucin and lactucopicrin. The last detailed research I know of appeared in 1976.

3. Recent writers generally don’t think much of lettuce. Tyler’s Honest Herbal (1999) calls lettuce opium a “venerable fraud of a drug.” The authors say it was popular in the U.S. during the 19th century but sank into obscurity in the 20th. In the mid-1970s, lettuce opium “was resurrected as a legal psychotropic or mind-altering drug by members of the American hippie movement”; one dealer reportedly cleared $1,500 daily selling lettuce products, which any way you look at it is a lot of lettuce.

4. A 1981 article in the prestigious journal Science claimed that lettuce contains 2 to 10 parts of morphine per billion. To put that in perspective, the usual therapeutic dose of morphine is 0.5 to 50 parts per thousand, roughly a million times as much.

5. A 1982 study of three “narcotic substitutes” sold in health-food stores and claiming to contain, among other things, a distillate of garden lettuce found no psychoactive compounds.

6. According to a 1998 report, three drug enthusiasts mixed up an extract of wild lettuce (one also tried valerian root), injected it, and came down with fever, chills, headache and other pain, neck stiffness, etc, for three days.

7. Lest the news appear all bad, in 2003 a French medical journal reported that a 23-year-old héroïnomane par voie nasale (heroin sniffer) ate a paste made from wild lettuce leaves he’d purchased online and said he felt des effets euphorisants et analgésiques. Then again, the article also says a 22-year-old Moroccan woman who ate wild lettuce stems fell into a coma and died. Hard to argue with Tyler: “Sensible people may continue to eat lettuce in their bacon and tomato sandwiches, but they will not smoke it in their pipes.”

Dear Cecil:

Your 1986 column on the lost Dauphin should be updated. (“The Straight Dope: Was naturalist J.J. Audubon really the dauphin who would have become Louis XVII?,” January 3, 1986.) A heart long said to have belonged to Louis-Charles — stolen by the doctor who performed the 1795 autopsy — was identified as sharing DNA with Marie Antoinette in 2000. (The history of the heart for the last two centuries is decidedly lurid, with plenty of opportunities for a switch, but since it apparently is authentic, no switch seems to have been performed.) The heart was officially interred in the royal crypt at the Saint Denis Basilica on June 8 of this year.

— John W. Kennedy, via the Straight Dope Message Board

Cecil replies:

Actually, the most complete DNA match was with a hair sample from Marie Antoinette’s sister, but close enough. It’s now almost certain that the Dauphin — heir of Louis XVI, the king guillotined during the French Revolution — did not escape as rumored for 150-plus years but died in prison of tuberculosis as officially claimed. The heart’s odyssey was indeed lurid — it was stolen from the pathologist who stole it in the first place (what is it with pathologists filching body parts, anyway?), returned, given to the archbishop of Paris, almost destroyed when the archbishop’s palace was sacked in the revolution of 1830, miraculously retrieved, given to the duke of Madrid, stored in an Austrian chateau occupied by the Nazis during WWII and then looted by the Russians, rescued by the duke of Madrid’s granddaughter, returned to the royal crypt at Saint-Denis, hacked at for the DNA test, then returned to the crypt, one hopes once and for all.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.