Diarrhea in dogs during their heat cycle can be distressing for both pets and owners.
We outline the common causes of diarrhea in dogs during their heat cycle, what you can do at home, and when to seek veterinary help.
Dog Diarrhea Due to Heat Cycle — Why It Happens
Dog diarrhea due to her heat cycle happens because of hormonal changes, stress, and underlying health conditions can all contribute to digestive upset during this time. Hormonal changes during a dog’s heat cycle can affect her entire body, including the digestive system.
Shifts in estrogen and progesterone can influence gut motility and cause loose stools. Stress from behavioral changes, reduced appetite, or changes in activity can also disrupt digestion.
Also, the immune system may be slightly compromised, making her more vulnerable to infections that trigger diarrhea.
Common Causes of Diarrhea in Dogs During Heat Cycle
Hormonal Imbalance
Hormones like estrogen and progesterone fluctuate significantly during a heat cycle. These hormonal surges can alter the way the intestines process food and water, leading to softer stools or diarrhea.
Owners might notice other signs such as mood swings, increased urination, or restlessness.
While mild diarrhea may resolve on its own, persistent or severe symptoms could indicate a more serious hormonal disturbance.
Read more: Dog Diarrhea Due To Stress (Here’s why)
Stress and Anxiety
The heat cycle can be a stressful period for many dogs. Changes in behavior from seeking mates, being kept away from male dogs, or even a shift in household routines can increase stress levels.
Stress can disrupt the balance of gut bacteria and speed up digestion, resulting in diarrhea.
This type of diarrhea may appear suddenly and be accompanied by pacing, whining, or clinginess.
Dietary Indiscretion
Some dogs may eat less during heat, while others might seek out unusual foods or chew on inappropriate items.
Hormonal influence on appetite can lead to sudden dietary changes, which may irritate the digestive tract.
Consuming fatty, spoiled, or unfamiliar foods can cause inflammation in the intestines, leading to loose stools and possible vomiting.
Secondary Infections
A dog’s immune system can be slightly weakened during her heat cycle. This may make her more susceptible to bacterial, viral, or parasitic infections that cause diarrhea.
You might notice symptoms like lethargy, fever, or mucus in the stool along with diarrhea. These cases require prompt veterinary evaluation.
Underlying Gastrointestinal Conditions
Some dogs have chronic conditions such as inflammatory bowel disease or food allergies that can flare up during hormonal shifts.
During the heat cycle, these underlying issues may become more pronounced, causing diarrhea, weight loss, and reduced energy.
Pyometra (Uterine Infection)
While pyometra primarily causes reproductive symptoms, it can also lead to diarrhea due to systemic infection and toxin release.
Signs include a foul-smelling vaginal discharge, lethargy, fever, and abdominal swelling.
This is a medical emergency and requires immediate veterinary attention.
What to Do If Your Dog Has Diarrhea During Her Heat Cycle
If your dog’s diarrhea is mild and she is otherwise acting normally, you can start by offering small amounts of a bland diet such as boiled chicken and rice.
Keep her hydrated with fresh water and monitor her closely.
Avoid giving treats, table scraps, or sudden food changes during this time.
Provide a quiet, comfortable space for her to rest, as minimizing stress can help her digestion recover.
If she refuses food for more than 24 hours, becomes lethargic, or develops additional symptoms, a vet visit is warranted.
When to Call or Visit Your Vet
If diarrhea lasts more than 48 hours, contains blood, or is accompanied by vomiting, lethargy, fever, or a foul-smelling vaginal discharge, seek veterinary care immediately.
Sudden worsening of symptoms, signs of dehydration, or any suspicion of pyometra should prompt an urgent appointment.
Early intervention can prevent complications and ensure your dog’s heat cycle passes as safely as possible.
Read more: Dog Diarrhea Due to Antibiotics (Here’s why)
Key Takeaway
Diarrhea during a dog’s heat cycle is often linked to hormonal changes, stress, or temporary digestive upset, but it can also signal serious health concerns.
Monitor your dog closely, provide supportive care at home, and don’t hesitate to seek veterinary help if symptoms persist or worsen.
By staying attentive and proactive, you can help your dog navigate her heat cycle with minimal discomfort and prevent complications.