We know there is a lot of "treasure" worth discussing in dramaland, but please keep your comments geared around the topic at hand so the people who want to participate can easily grab their shovels and treasure map.

Only drama that comes to my mind immediately reading the word lethal is
I am not a robot where Kim Min kyu gets those terrible rashes as allergic reaction to human touch.

K-drama All that we loved (2023). One of the main leads has peanut allergy.

Peaches really are a thing aren't they? Ung is allergic to peaches in Our Beloved Summer, and so is his friend Ji-ung. Maybe it doesn't count as an allergy, but the oldest brother (original CP) in Our Blooming Youth died from eating a peach, but it was some kind of hyper-sensitivity because of other medication he was on. I know there was an instance in Crazy Love too, but I haven't seen it (just read weecaps).

Can Beanies think of other peach-allergic characters? I feel like there's another that I'm not thinking of...

Pretty sure in HIGH BYE MAMA, the child had a strawberry allergy.

You're Beautiful - Tae Kyung had a shrimp allergy, if I remember correctly.

TotNT - young Jia and um - walnut? - cookies?
Perfume

Does lactose intolerance count here? Because there’s “Anthony” in Hello, Me!

Not a kdrama, but c-romcom LOVE IS SWEET

Do Min-ik in The Secret Life of My Secretary has peanut allergy. It was used quite well in the plot for Do Min-ik to uncover the secret between his secretary and Veronica Park. The conversation about peanut allergy also help mended his relationship with his mother.

Joo Sang Wook's character in History of the Salaryman has a bad peanut allergy that becomes a recurring plot point.

Hi! School: Love On (ep. 4): Woo-hyun and his mother were allergic to shellfish.
The K2 (ep. 7): Anna got strawberry ice cream allergy.
Romance Is a Bonus Book (ep. 12): Hae-rin got cucumber allergy.

There were several patients in CHOCOLATE who had severe allergies.

Indeed there appears to be a Royal problem w peaches, from Goong all the way to Blooming Youth.

It seems like most characters have a severe allergy to alcohol although it never stops them from over drinking.

I vaguely recall a scene, but not which series, where the lead has dinner with his neglectful mother who doesn't know or remember he has some kind seafood allergy.

Rooftop Prince, the crown prince was allergic to crab.

Go Back Couple, BanDo was allergic to peaches.

Room No.9, this was a body swapping drama, one of the leads didn't know the body she is inside is allergic to peaches.

Being allergic to humans in I am not a robot

God's Gift: 14 Days, as I recall the kid had a peanut (or some other kind of nut?) allergy that was a plot point a couple of times (you'd think the kid would learn to ask "does this contain peanuts?")

Song Hwa was allergic to Ibuprofen in Hospital Playlist.
And she didn't know it.

You were exactly in my head when you mentioned Ryan Gold's lethal latte allergy in Her Private Life.

We had the nut allergy in Forecasting Love and Weather with Forecaster Um's daughter. Was that the only shrimp allergy in dramaland? I know there's another adult...was it the FL in 18 Again who reacted to shrimps?

I recall the ML in WWWSK having a particular nuts allergy like that as well.

And then we had those who's allergies were not foodwise. Like being allergic to sound and sight à la our ML Yoon Kye-sang in Kiss Sixth Sense. Or the germophobic ML in Clean With Passion For Now. And yes, I can't forget the peanut allergy of the Haraboji Lee's and his lost daughter in It's Beautiful Now.

Of all these allergies, Her Private Life's Ryan Gold's latte allergy stands out the most for me as the most lethal.

Had a student who said he was allergic to cucumbers. Would not have believed him unless witnessing that face blow-up of the second FL in Romance is a Bonus Book.

In One The Woman, the original Kang Min A is allergic to some kind of nuts, but the prosecutor who ends up impersonating her after losing her memory is not.

a lot of tsundere male leads are also allergic to idiots. Or the female lead, at first. wasnt there someone who sneezed every time the FL approached?

In Tale of the nine tailed, the FL (Ji-Ah) is allergic to a walnut and as a child effectively uses that to determine that her “mother” is really a demon after her parents die in a car crash and she wakes up with a set of parents impersonating her own. That scene was seriously disturbing to me. If I didn’t know Kim Bum and LDW were waiting for me on the other side of it, I’d probably have dropped that drama.

And a neglectful mother in Run On (I think) never remembers her son’s food allergy, and randomly fixes him food when she visits that he can’t even eat.

The male lead’s nut allergy in LOVE LIKE THE GALAXY is a pivotal plot twist.