ThreeLac contains probiotics which are supposed to "eat" or otherwise interfere with Candida, plus some supporting ingredients. The strains of the probiotic bacteria are claimed to be somewhat unique to ThreeLac. The total ingredients are:

Bacillus subtilis
Enterococcus faecalis
Bacillus coagulans

Vitamin C as ascorbic acid 75mg
Vitamin B6 as pyridoxine .4mg
Bitamin B1 as thiamine .4mg
Viatmin B2 as riboflavin .4mg

Refined Yeast Powder
Dietary Fiber as Galactomannan
Fructo-oligosaccarides (FOS)
Beta Cyclodextrin
Erythritol
Lemon Juice Powder
Canola Oil

Primal Defense, Threelac, and Syntol contain Bacillus Subtilis as their main active ingredient.
B. Subtilis is a strong antibacterial and is the basis for the antibiotic Bacitracin. There is no discrimination between which types of bacteria it will eliminate. Eliminating bacteria creates imbalances that drive the spread of fungal candida throughout the body and has been linked to acute problems such as diarrhea and life-threatening colitis to chronic problems such as obesity, cancers, and other conditions. While it does have antifungal and antiparasitic properties also, its strong antibacterial action could create lifelong imbalances, the same as any other antibiotic.

In amongst the information that these companies put out is this paragraph:

"The Germans analyzed the stools of the camels and discovered bacillus subtilus. It turned out that b. subtilus was so powerful that it practically eats all harmful micro-organisms in the human body, including fungi. Subsequently they figured out how to mass produce it and the troops no longer got dysentery."

The statement that it is so powerful that it eats all harmful organisms in the body should make anyone refrain from using it. B. substilis doesn't have an ability to distinguish good from bad organisms and in the end, the co-operative effect of all organisms is beneficial to the body. Destroying bacteria is what antibiotics do and is the main reason for systemic fungal candida and many of the problems related to antibiotics.