Addressing Constipation: Why and How

Something that can affect behavior in children with autism more than you might expect is constipation. It might seem like a minor issue, or we might not even realize it is an issue, because we sometimes hear from doctors that only 3 bowel movements a week is within the range of "normal." But in children with autism, symptoms like aggression, self-injurious behaviors (such as head-banging or hitting), irritability, anxiety, meltdowns, difficulty staying asleep, or toe-walking all can be caused or worsened by even mild constipation.

Why Constipation Affects Behavior in Autism

Unresolved constipation causes physical discomfort—abdominal pain, bloating, or pressure—that nonverbal or minimally verbal children may express through behavior rather than words. Chronic constipation also disrupts the gut-brain axis. It alters the gut microbiome, affects mitochondrial dysfunction, increases inflammation, and affects neurotransmitter production, all of which can amplify behavioral challenges in autism. GI symptoms are linked directly to:

• Higher rates of self-injurious behavior and aggression.

• Increased irritability, anxiety, and withdrawn behavior.

• Sleep disturbances and attention problems.

• Worsened repetitive or restricted behaviors.

  
  

In my personal experience, my son was once taken to the emergency room for inconsolable crying, yelling, and self-injury. They did an x-ray to make sure he hadn't fractured his skull, but in an abdominal x-ray found "moderate constipation." After an enema, his mood instantly improved. It had only been a couple days since he pooped! Now I make sure to never let it get to that point. We should be looking for 8-10 inches of stool each day, not hard, and passed easily.

Bristol Stool Chart from tacanow.org

Why Address Constipation Before Biomedical Interventions, including Gut Balancing

Addressing constipation is a necessary first step before starting any biomedical intervention, including gut balancing. This is because bowel movements are the primary mode of detoxification, as the liver excretes the toxins it has processed for elimination through the bile and into the digestive tract. If these do not pass through the bowel movements, there is the potential for them to be reabsorbed. Many interventions increase detoxification, and if these toxins are not actually able to find their way out, it may make symptoms worse.

In gut balancing, as bacteria shift, toxic metabolites are released. The body’s detoxification load increases, which can slow motility and strain mitochondria (the cell’s energy producers).

Supporting motility first creates a smoother foundation. A backed-up colon makes it harder for beneficial microbes to thrive, reduces the effectiveness of interventions, and heightens the risk of die-off symptoms (Herxheimer reactions) that manifest as behavioral regression. Addressing constipation proactively minimizes discomfort, supports better nutrient absorption, and helps the gut environment become more receptive to positive microbial changes.

Concerns with Miralax (Polyethylene Glycol 3350)

Miralax is a common osmotic laxative that draws water into the intestines. While it provides short-term relief, many parents of children with autism report concerns, including:

• Neuropsychiatric side effects — such as increased anxiety, aggression, mood swings, obsessive-compulsive behaviors, tics, or personality changes. The bacteria in the microbiome have the potential to convert polyethylene glycol to ethylene glycol, which is antifreeze.

• Off-label use in children (not FDA-approved for long-term pediatric use).

• Long term microbiome changes, wiping out certain species, causing overgrowth of others, and impairing the production of short-chain fatty acids (SCFAs) which keep the colon healthy

• Potential for dependency, electrolyte imbalances, or trading constipation for diarrhea and bloating.

  
  

Because children with autism may already have altered gut permeability and sensitivities, many families prefer gentler, food-based, or herbal alternatives that support natural peristalsis without synthetic additives.

A Toolbox of Natural Motility Supports

Here is a list of good ways to get the bowels moving. These can be introduced individually or layered as needed. Always consult your practitioner before starting, especially for children, and monitor individual responses. Several of these can be found on Fullscript here.

• Food-Based Vitamin C (250–1000 mg): Helps with constipation and combats reactive oxygen species; also supports histamine breakdown.

• Ginger (1–3 capsules, e.g., Nature’s Way): Acts as a prokinetic, stimulating acetylcholine release to enhance peristalsis; reduces inflammation and helpful for SIBO-related issues.

• Fennel Seed (1–3 capsules): Reduces gas by lowering surface tension of bubbles and relaxes digestive muscles.

• Magnesium Citrate (150–500 mg, e.g., Pure Encapsulations): Osmotically draws water into the intestines; also supports mitochondrial function.

• Lactulose (1–5 ml, note: some US brands contain dyes/sweeteners): Retains water, promotes short-chain fatty acid (SCFA) production via bacterial fermentation, stimulates colonic smooth muscle, and helps trap ammonia for excretion.

• Serene Calm (follow label; for adrenal support): Cortisol influences baseline gut motility and enteric neuron responsiveness.

• Senna (follow label; short-term use only): Stimulant laxative that activates the myenteric plexus for colonic peristalsis.

• 3-Strain Probiotic (1–3 capsules): Boosts SCFA production to stimulate propulsive peristalsis.

• Peppermint Leaf (1–3 capsules): Antispasmodic; promotes coordinated peristalsis and eases gas.

• PHGG (Sunfiber) (1–2 tsp): Forms a soft gel-like bulk, supports SCFA production, lowers colonic pH, and minimizes gas compared to other fibers.

• Prune Juice (4–12 oz): Osmotic + mild stimulant effects from sorbitol and phenolic compounds.

• Aloe Vera Juice (1–2 oz): Milder stimulant than senna; supports the myenteric plexus.

• Concord Grape Juice (4–12 oz): Osmotic effects plus anthocyanins and phenolics that stimulate motility.

• Flaxseed Powder (¼–1 tsp): Soluble fiber absorbs water; provides omega-3s and promotes SCFA production.

• Triphala (250–750 mg): Gentle combination of amla, bibhitaki, and haritaki; offers mild stimulant, osmotic, and regulatory effects.

• Other options: Mega Motility (multi-component formula), TTFD thiamine (for nerve and energy support in slow transit), or cascara sagrada (short-term, milder than senna).

  
  

Lifestyle basics remain foundational: adequate hydration, movement (even gentle walking or play), abdominal massage, and a fiber-rich diet with whole foods.

Final Thoughts

Constipation is a medical issue that deserves proactive, compassionate attention—not dismissal as “just part of autism.” Clearing it can reduce pain-driven behaviors, improve quality of life, and set the stage for more successful gut-healing work. While pharmaceutical options like Miralax might provide short-term relief, it may worsen the gut and behavioral symptoms long term. Balancing the gut, aiming for a healthy diet and good hydration, and adding motility supports as needed provide a foundation to seeing health and behavioral improvements in children with autism.