Then she heard the phone ring. It was me, calling to see if she was feeling any better. Luckily, she was able to reach over, pick up the receiver and mumble to me about what was going on. I called her gynecologist, who told me to take her to the hospital. When the cab got me home from the office, I found Diane lost in her closet. She stammered that she wanted to get dressed to go out but couldn't find her white shirt. I looked down and saw that it was an inch from her hand.

Married people can afford to panic only one at a time, so I pretended I was not scared as I helped her on with the shirt and took her to the hospital closest to where we live in Philadelphia, which happens to be Pennsylvania Hospital, the oldest hospital in America and one of the very best. As Diane spoke haltingly, elliptically to the ER doctors, more symptoms emerged. Her jaw was terribly sore from clenching against what we assumed had been a seizure. Her pupils were fixed and dilated, like blobs of black ink. She said she felt as though something were "melting" just behind her green eyes.

It was late Friday afternoon at the ER, just before the weekend rush, so we got a good, slightly private, curtained-off area. An emergency medicine specialist and several neurology residents tag-teamed in and out of our space. Each one asked a slightly different version of the same questions. I worried that we weren't being clear because there didn't seem to be any accumulation of knowledge taking place. They all had tests they wanted Diane to perform.

"Spell the word 'world' backwards," one asked. She did it and was then asked to name the U.S. presidents in reverse chronological order.

"Can you spell 'world' backwards?" the next one asked. Then he requested that she touch her finger to her nose.

"I'd like you to try to spell ..." the next one began.

"Yeah, yeah," Diane said, "'world' backwards." But she was bobbing in and out of full lucidity. Only seconds after cracking a joke, her mind would be sluggish again, and she would barely respond when I stroked her cheek or her shoulder-length brown hair.

After nearly five years of marriage, this was the first medical emergency we ever had to face. The only thing that kept me from really losing it was a woman in the next cubicle who already had lost it. Dragged in by the police in the middle of a major psychotic episode, she screamed continually in English and Chinese about everything from her husband's homosexuality to her close personal friendship with the president of the United States. Her screams pierced the crackly trauma calls from ambulances all over the area, which were being broadcast on a loudspeaker system for the ER staff to monitor. The combined noise was oddly stabilizing, a constant reminder that things could be considerably worse.

After several hours of neurological exams, the word came back -- from a place called the Poison Control Center -- that all of Diane's symptoms had been previously reported as reactions to the antibiotic she took. The drug is called Floxin. She had, as we now say, been "Floxed."

My wife took a pill. It made her sicker than she was before. World backwards. Tell me about it.

The ER doctors, however, were not through with us. They still wanted to run more tests. Even though Diane's symptoms, such as "acute delirium," were consistent with a reaction to the Floxin, they could also be caused by a brain tumor, a stroke or a big horrible infection with larger neurological implications, like spinal meningitis. They wanted to do a CT scan.

I got to sit in the CT control room and watch the machinery visually slice and dice. There is nothing quite so frightening as watching your loved one's brain being scanned for tumors, especially when you're not exactly sure what a normal brain looks like. But it is also very moving to peer directly into your wife's mind. What spouse hasn't at one time or another wished to be able to do that?

Back in the ER after a clean scan, we were then told the prevailing wisdom about all adverse drug reactions: that the effects would subside when the medication left her system. And we were sent home -- with a supply of the milder, cheaper antibiotic she probably should have taken in the first place for her urinary tract infection -- to wait for that to happen. On our way out, we walked past the main ER desk. On the wall behind it was a light box for reading X-rays, which was still illuminating pictures from the inside of Diane's brain. To the left of the viewer was a shiny metal towel dispenser. It was adorned with Floxin advertising magnets that had been left by some enterprising drug sales rep.

At that moment I thought the Floxinalia would actually make a nice detail for our emergency room horror story, the recitation of which would commence as soon as Diane was fine, ostensibly in a couple of days. But her symptoms did not disappear as promised. Some waned, but new ones developed. Besides the "melting" and the fixed pupils, she had really aggressive, buzzy insomnia, visual distortions that made the world seem six-dimensional and aphasia: She would get halfway through a sentence and just couldn't get the rest of the words out. For a woman with a high school trophy for "best negative debater" sitting on a shelf behind her desk, this was probably the scariest symptom of all.

Over the next two weeks, she endured an electroencephalogram, which tests electrical function in the brain; a magnetic resonance imaging of her head, which offers more structural detail than the CT scan; and a spinal tap, to check the cerebrospinal fluid for infections, as well as some blood work. All these tests just to rule out any other possible explanation for her continuing symptoms than an adverse reaction to the drug -- the same drug that was supposed to be long gone from her system. While the tests themselves were creepy, what they were testing for was absolutely horrifying. I found myself weighing which awful result would be most acceptable, watching the life we had planned to have pass before my eyes.

The tests all came back on a Thursday, one of the most harrowing days of our lives. As we were read the results over the phone by our internist, I found myself mentally checking off all the nightmares that had been eliminated by the process -- "brain tumor, no; stroke, no; AIDS, no." But Diane still wasn't well. The doctors concluded that the drug reaction had triggered some genetic predisposition to neurological illness. Since her body hadn't been able to correct the situation naturally, she would need to take a combination of heavy-duty drugs, each with its own possible side effects, to do it. If, in fact, it could be done at all.

But at least that urinary tract infection had cleared up.