Q: A few years ago, I was unable to remove a splinter from my hand. Ultimately, it calloused over but was still bothersome.

In desperation, I searched the internet to find out how to remove it and viewed a video that told how to use a raisin to get it to surface. The result wasn’t immediate, but I was persistent. After about a week of taping a fresh raisin over the spot daily, the splinter emerged.

More recently, a rose thorn went through my garden glove and embedded itself in my hand. I covered it with a raisin and bandage. The next morning the thorn had emerged enough that I could grab it and pull the quarter-inch thorn out. Can you please explain the magical properties in raisins?

A: We wish we could! We retraced your internet search and found a similar video demonstrating this remedy. We have written for years about using a wart plaster with salicylic acid over a stubborn splinter. This was written up in the medical literature (Journal of the American Academy of Dermatology, April 1989).

Raisins are high in salicylates, so perhaps that helps explain this unusual effect. Some people advocate cutting the raisin in half and applying the cut surface to the skin for a day to encourage the splinter to work itself out.

Q: I have IBS. Sometimes this causes constipation, sometimes sudden urges with soft stool. I thought I saw something recently that said vitamin D helps with IBS. Is this true? How much vitamin D should I be taking?

A: Irritable bowel syndrome (IBS) can cause a great deal of discomfort, though doctors do not consider it a dangerous disorder. The usual symptoms are bloating, stomach cramps and changes in bowel habits. Some people experience diarrhea, others are constipated, and still others, like you, alternate between the two.

We were intrigued by your suggestion that vitamin D supplements might be helpful. Checking the medical literature revealed a randomized controlled trial of vitamin D vs. placebo for IBS symptoms (European Journal of Nutrition, July 30, 2021).

We are sorry to say that 3,000 IU vitamin D daily for three months was no more effective than placebo. The authors conclude: “There is no case for advocating use of vitamin D in the management of IBS symptoms.”

Q: When is the best time to take high blood pressure meds? Morning or night?

A: Doctors often recommend that patients take their blood pressure pills in the morning. The reasoning is that a morning routine will help people remember to take the medicine. Also, blood pressure is usually higher when people are up and active than when they are in bed.

The evidence does not support this recommendation, however. A recent review of 155 randomized controlled trials compared people taking their medicines in the morning or in the evening (Chronobiology International, October 2021). A significant majority of these trials found better blood pressure control when people took their pills at bedtime. None of them found that taking the pills in the morning worked better.

Diuretics could be an exception, though. Taking such water pills in the evening might lead to excessive urination during the night.

In their column, Joe and Teresa Graedon answer letters from readers. Send questions to them via www.peoplespharmacy.com.