Some people (believe it or not) have a mild stimulus with drinking warm water. As hot as you can stand. This tends to
stimulate the GI tract for some reason.
Also virgin olive oil is laxative for some people. At least 2 tablespoonfuls.
Some people find Miralax useful. This is OTC now.
I'd be careful with Senna products however, as they are being
looked at as potential cancer causing agents when used every day for long periods of time. Here and there is okay, but until the verdict is finally in on this potential, I'd be careful with them.
Here is one site with some suggestions about Senna:
Magnesium oxide products may work for some people. They come in tablets, made in US by Phillips. Also most doctors suggest trying Milk of Magnesia as a first thing.
Some people make up a paste consisting of prunes, figs etc.
Pear juice helps some people. Some of the paste recipes I've found include Senna. But you could try them without. Just Google "fruit paste for constipation".
Sorbitol is also a mild laxative. Some dietetic candies are high in sorbitol. You have to read the labels to find which ones.
I remember when I bought some sugar free PEZ candies for my son's PEZ dispenser. We didn't look at the ingredients (my BAD) and within a hour he was in major distress! He was about 7 or so. Sorbitol is a liquid used in RX compounding as well, and commonly prescribed by doctors for patients in nursing homes on high dose opiates. Lactulose is another liquid some may try. Doctors typically order sorbitol or lactulose on RX.
Alot depends on the person. Some people need stronger help than others.