Laughter is the best medicine—and I learned this the hard way when my sister insisted on coming with me to my chemo treatments for breast cancer 12 years ago. When they say “the cure is worse than the disease,” they’re probably referring to my sister’s endless supply of terrible jokes and bad puns.

When Diane is nervous she babbles and makes silly jokes, a sore point in the family. But in a hospital waiting room where you’re nervous and distracted, this kind of non-stop nonsense can actually be soothing. Diane’s stupid jokes acted as a kind of comic “white noise” that shielded me from my own distinctly non-hilarious thoughts.

I welcomed Diane’s groaners and rim shots, her one-liners and shaggy-dog stories. I can’t say the same for the other people sitting nearby. “Do you think they’re bothered by your relentless jokes and our high-pitched cackles?” I whispered to Diane.

“Nah,” she said. “And did you hear the one about the priest, the rabbi and the radiation oncologist?”

Studies show that laughter is medically beneficial. Nowhere was this more in evidence than when Diane accompanied me for a blood test for tumor markers. According to Diane, “I made you laugh so hard that your blood pressure rose, the blood poured out and the grueling ordeal was over before you knew it.”

Funny, the only thing I remember was the smelling salts and the bright lights returning.

Our mother, by the way, was scandalized by Diane’s sense of humor and our twin hyena laughter. Mom’s idea of sitting by my side involved asking me 12 times whether I needed a Kleenex or a sweater. “Are you cold? Are your sinuses okay?”

When Diane would recite a disreputable ditty our father had taught us from his Army days, Mom would pretend that she wasn’t our mother. She just happened to be in the neighborhood and stopped into the breast cancer clinic for the magazines.

Diane became my personal cancer jester from the moment she went with me to “pre-op,” where they take your blood and kick your tires to see if you’re ready for the next day’s surgery.

“Pre-op,” repeated Diane loudly, looking at the form I had to sign. “Is that like a trial run-through? Are they practicing for tomorrow to develop muscle memory?”

We laughed till we shrieked and snorted and choked—which for some reason offended all those Gloomy Gus cancer patients who were still waiting their turn.

“The poor things,” Diane clucked. “They probably need to be taught how to laugh in the face of life’s setbacks!”

Diane had her own experience with cancer a year later. It didn’t stop her from making the same stupid jokes to relieve the tension.

Today my sister and I are both healthy. People who are newly diagnosed with cancer sometimes come to us for advice—but if they want Kleenex or a sweater, they should try my mother. Diane and I know that laughter is the best medicine, and we intend to keep doling it out without a license.

Jami Bernard is the author of Breast Cancer: There & Back and helps people tell their stories and get published through BarncatPublishing.com.