Kennedy suffered severe health problems almost from the time of his birth. Three months before he turned three, in 1920, he came down with a bad case of scarlet fever, a highly contagious illness, and life-threatening for so small a child. He spent more than two months in the hospital and recuperating in a Maine sanatorium.
During the 1920s he suffered from a variety of other childhood maladies, including bronchitis, chicken pox, ear infections, German measles, measles, mumps, and whooping cough. His illnesses filled the family with anxiety about his survival.
In 1930, at age thirteen, Jack was afflicted with an undiagnosed illness that restricted his activities. From October to December he lost four to six pounds, felt "pretty tired," and did not grow. One doctor attributed it to a lack of milk in his diet, but that failed to explain why during a chapel service at the Canterbury School, his boarding school in New Milford, Connecticut, he felt "sick dizzy and weak." He wrote to his father, "I just about fainted, and everything began to get black so I went out and then I fell and Mr. Hume [the headmaster] caught me. I am O.K. now." In April of 1931 Jack collapsed with abdominal pains, and the surgeon who examined him concluded that it was appendicitis and that an operation was necessary at a nearby hospital in Danbury, Connecticut.
The operation did not solve the problem. In the fall of 1932, while boarding at the Choate School, in Wallingford, Connecticut, Jack complained of abdominal discomfort and fatigue. His weight was only 117 pounds—less than robust for a fifteen-year-old boy. In January and February of 1933 "flu-like symptoms" plagued him, along with almost constant pain in his knees. "Jack's winter term sounded like a hospital report," an official fiftieth-anniversary remembrance of his attendance at Choate recounted, "with correspondence flying back and forth between Rose Kennedy and [the headmaster's wife]. Again, eyes, ears, teeth, knees, arches, from the top of his head to the tip of his toes, Jack needed attention."
Over the summer of 1933, after he had turned sixteen, he gained no weight. And matters got worse the following year. In the winter of 1934 he became very sick and had to be rushed by ambulance to New Haven Hospital for observation. His symptoms included weight loss and a bad case of hives. Doctors feared that he had leukemia and began regularly checking his blood counts. "It seems that I was much sicker than I thought I was," Jack wrote to his classmate LeMoyne Billings after he got out of the hospital, "and am supposed to be dead, so I am developing a limp and a hollow cough." His rectum was "plenty red after the hospital," he complained. "Yours would be red too if you had shoved every thing from rubber tubes to iron pipes up it." By March, Jack's symptoms had largely disappeared, but his doctors remained uncertain about the cause of his difficulties.
In June of 1934, as his junior year at Choate ended, he began feeling ill again, and his parents sent him to the famous Mayo Clinic, in Rochester, Minnesota. He spent a miserable month there, "the God-damnest hole I've ever seen," he wrote to Billings. By himself at the Mayo and then at nearby St. Mary's Hospital, where he was transferred after two weeks, he maintained his sanity and kept up his hopes for a return to friends and family through a series of such letters. Jack handled what he feared was a life-threatening disease with a biting wit and a refusal to complain openly to anyone but his friend. Judging from the medical tests described in the correspondence and in later medical records, Jack had colitis, which was initially thought to be peptic-ulcer disease. The doctors began by prescribing a diet of bland food preparatory to tests that Jack had hoped would be over in a few days. But the exams lasted much longer. "I am suffering terribly out here," he wrote to Billings. "I now have a gut ache all the time. I'm still eating peas and corn for my food." He expected to be there for at least another twelve days. Two days later he told Billings, "God what a beating I'm taking. I've lost 8 lbs. And still going down ... I'm showing them a thing or two. Nobody able to figure what's wrong with me. All they do is talk about what an interesting case."
"It would be funny," he declared wishfully, "if there was nothing wrong with me. I'm commencing to stay awake nights on that. Still don't know when I'll get home. My last eight meals have been peas, corn, prunes."
Six days later he gave Billings another graphic description of his ordeal. "I've got something wrong with my intestines. In other words I shit blood." He feared he might be dying. The doctors were still trying to determine the cause of his illness. "Yesterday I went through the most harassing experience of my life," Jack wrote. "[A doctor] stuck an iron tube 12 inches long and 1 inch in diameter up my ass ... My poor bedraggled rectum is looking at me very reproachfully these days ... The reason I'm here is that they may have to cut out my stomach!!!!—the latest news."
All the gastrointestinal and colon tests indicated that Jack had colitis and digestive problems, which made it difficult for him to gain weight and threatened deadly consequences if the colon became ulcerated or bled.
Judging from accounts published in the January 1934 and December 1936 issues of the Mayo Clinic journal, Proceedings, the clinic's usual therapy for colitis involved a combination of restricted diet; relief of emotional stress, which was assumed to be a major contributor to both colitis and ulcers; and injection of a serum obtained from horses. Although the clinic claimed a measure of success with this treatment, it was clearly no panacea. Corticosteroids, which research centers were then testing, seemed more promising in the treatment of a whole variety of illnesses.