It is generally used for nausea and vomiting of pregnancy (morning sickness); even though its efficacy has not been proven and subsequent research has led to the removal of recommendations in medical journals.

"[6] The American Family Medicine recommends, "Initial treatment is conservative and includes dietary changes, emotional support, and vitamin B6 supplementation.

"[7] Canadian Family Physician issued a correction stating previous articles which stated Diclectin should be used as a first line therapy were incorrect, based upon undisclosed conflicts of interest with the manufacturer, and not peer-reviewed studies:"Recommendations in 2 articles published in Canadian Family Physician, “Nausea and vomiting of pregnancy.

Additionally, for the articles in Canadian Family Physician there was an undisclosed conflict of interest with Duchesnay, the manufacturer of Diclectin, the combination of doxylamine-pyridoxine.

[11] Other adverse drug reactions associated with doxylamine succinate may include: vertigo, nervousness, epigastric pain, headache, palpitation, diarrhea, disorientation, irritability, convulsions, urinary retention or insomnia.

[16] A study was conducted to determine whether the combination drug of pyridoxine and doxylamine had an effect on the neurodevelopment of children exposed in utero.

[19] In litigation, Bendectin was implicated as the cause of various fetal malformations and problems including limb and other musculoskeletal deformities, facial and brain damage, defects of the respiratory, gastrointestinal, cardiovascular and genital-urinary systems, blood disorders and cancer.

[20] The star witness for the case against Bendectin, William McBride, was later found to have falsified research on teratogenic effects of the drug, and was struck off the medical register in Australia.

[23] The FDA, in 1999, published a statement in the Federal Register that summarized their opinion regarding the safety of pyridoxine/doxylamine during pregnancy: “The FDA has determined that the drug product Bendectin, a tablet composed of pyridoxine hydrochloride 10 mg, and doxylamine succinate 10 mg, for the prevention of nausea of pregnancy was not withdrawn from the market for reasons of safety or effectiveness”.

Navindra Persaud, Jessica Chin, and Mark Walker wrote a public letter to the Journal of Obstetrics and Gynaecology of Canada and raised concerns over the risks of Diclectin and recommended reconsidering it as the "first-line pharmacological treatment" against the nausea and vomiting of pregnancy.

[29] Dr. Persaud shared with news agencies that his only source of research data for this drug came from Health Canada and claimed he was only able to access the document by signing a confidentiality agreement.

Additionally, for the articles in Canadian Family Physician there was an undisclosed conflict of interest with Duchesnay, the manufacturer of Diclectin, the combination of doxylamine-pyridoxine.