Threelac is a good product and works well for many, but it is not a panacea. There are people it has not worked for. Do not become discouraged if it doesn't work for you. Not everyone is the same.
Also, while Threelac may have caused some people to expel some worms or a portion of a tapeworm, there is nothing in its formulation that acts as an anthelmintic for either round or tape worms. The expulsion noted likely was due to increased peristaltic activity in the gut and does not indicate that a thorough and complete worming has taken place.
Failure to improve with Threelac or any other probiotic may indicate the presence of a mixed infection involving bacteria or fungi other than Candida, or may indicate the involvement of other factors such as allergies as in Celiac disease which the probiotic would not address.