Yes it can. It all boils to the endocannabinoid system (ECS). The ECS is largely devoted to maintaining homeostasis (the tendency of organisms to auto-regulate and maintain their internal environment at equilibrium). Deficiency or malfunction of the ECS has become a focus for researchers seeking treatment options for several maladies—especially those that have few, if any, effective pharmocotherapeutic interventions, such as celiac disease, MS, fibromyalgia, IBD and IBS. In fact, the scientific community has recently termed the ECS malfunction: Clinical Endocannabanoid Decifiency, or CEDC.
CBD works by balancing and supporting the ECS through its subtle effects on cannaboinoid receptor-1 (CB1) and cannaboinoid receptor-2 (CB2) receptors, as well as other receptors that modulate serotonin, GABA, dopamine, and many more.
In IBS, IBD and GERD, like most every physical-chronic condition, inflammation is central to both the etiology and symptomology of the respective disease. CBD works to reduce inflammation by restoring balance to the ECS.
The main culprit for acute and chronic inflammation in the gut is hyperactive enteric glial cells, which proliferate and release neurotrophins, growth factors, and pro-inflammatory cytokines that may overamplify the immune response. Recent pre-clinical research suggests that CBD may lower GI inflammation by controlling reactive gliosis in the enteric (GI) nervous system. Or, in other words, CBD restores homeostasis in the gut by reducing hyperactivity in enteric glial cells.
Furthermore, several studies show that among patients who seek medical attention for IBS or IBD, around 70% of IBS patients, and 30% of IBD patients, have psychiatric comorbidity—depression and generalized anxiety disorder being most common. CBD increases serotonin signaling at the 5-HT1A receptor—the same neurotransmitter and receptor that SSRIs like Prozac influence—which is mostly why CBD has antidepressant and anxiolytic properties. In fact, SSRIs and tricyclic antidepressants (which also increase serotonin signalling), have been shown to alleviate anxiety and depression symptoms, as well as alleviate some of the abdominal pain and bowel symptoms involved in IBS, IBD and gastroesophageal reflux disease (GERD), which is why SSRIs and TCAs are commonly prescribed for IBS and IBD.
I hope this helps!