Urinary tract infection symptoms: blood in the urine

Blut im Urin (Hämaturie) kann ein Symptom einer Blasenentzündung sein, doch es gibt auch viele andere mögliche Ursachen. Während eine leichte Blasenentzündung oft harmlos verläuft, kann Blut im Urin auf eine stärkere Entzündungsreaktion oder eine ernsthafte Erkrankung wie Harnsteine, Prostataerkrankungen oder sogar Tumoren hindeuten. Auch Medikamente oder Verletzungen der Harnwege können zu Blutbeimengungen im Urin führen. Die genaue Ursache lässt sich durch Urintests, Ultraschall oder eine Blasenspiegelung abklären. Bei anhaltender oder stark ausgeprägter Hämaturie ist ein Arztbesuch unumgänglich. Hausmittel wie viel Flüssigkeit, Blasen- und Nierentees oder Cranberry-Präparate können unterstützend wirken, ersetzen aber keine medizinische Abklärung. Besonders gefährlich wird es, wenn Blutgerinnsel im Urin auftreten, Fieber oder starke Schmerzen hinzukommen oder das Blut über mehrere Tage hinweg sichtbar bleibt. Eine gezielte Behandlung – ob mit Antibiotika, entzündungshemmenden Maßnahmen oder medikamentöser Therapie – kann helfen, die Blasenschleimhaut zu schützen und Komplikationen zu vermeiden.

Autor

Philip Schmiedhofer, MSc

July 12, 2026

Inhaltsverzeichnis

Is blood in the urine always a sign of a bladder infection?

Blood in the urine (hematuria) can be a symptom of a bladder infection, but it is not always a clear indication of it.

When is blood in the urine dangerous in a bladder infection?

Blood in the urine (hematuria) can be harmless in a bladder infection but may indicate a serious complication in certain cases.

What other causes can blood in the urine have?

Blood in the urine occurs when the mucous membranes of the bladder are irritated or injured by inflammation.

What does urine look like with a bladder infection?

Urine can visibly change during a bladder infection.

When should you see a doctor for blood in your urine?

Blood in the urine (hematuria) is a serious symptom that should always be examined by a doctor.

What tests are necessary for blood in the urine?

To determine the cause of blood in the urine, the following examinations can be performed.

How often does blood appear in the urine with bladder infections?

Blood in the urine (hematuria) is a possible but not always occurring symptom of a bladder infection.

Can a bladder infection with blood in the urine heal on its own?

A mild bladder infection can sometimes clear up on its own if the immune system is strong enough to fight the infection.

How long does blood in the urine last with a bladder infection?

Blood in the urine (hematuria) can last for varying lengths of time with a bladder infection, depending on the severity of the infection.

Are there home remedies for blood in urine with a bladder infection?

Blood in the urine during a bladder infection can often be supported with home remedies, but these do not replace medical treatment.

Is blood in the urine always a sign of a bladder infection?

Blood in the urine (hematuria) can be a symptom of a bladder infection, but it is not always a clear indication of it. Various diseases and factors can cause blood in the urine, so medical evaluation is always recommended.

When is blood in the urine dangerous in a bladder infection?

Blood in the urine (hematuria) can be harmless in a bladder infection, but in certain cases may indicate a serious complication. Blood in the urine becomes particularly dangerous when accompanied by other symptoms or persists over a longer period. Blood in the urine should be taken especially seriously if additional symptoms such as severe lower abdominal pain, urinary retention, or a general feeling of illness occur. Early medical consultation can help prevent serious complications such as a kidney infection or advanced bladder disease.

What other causes can blood in the urine have?

Blood in the urine occurs when the bladder mucosa is irritated or injured by inflammation. This can have the following causes:

Strong inflammatory reaction: The infection attacks the sensitive bladder lining, which can damage small vessels.
Mechanical irritation: Frequent urge to urinate and cramping urination can additionally strain the bladder wall.
Intense bacterial colonization: Some pathogens (e.g., Escherichia coli) can aggressively attach to the bladder lining and damage it.
Increased permeability of blood vessel walls: Inflammatory processes cause small amounts of blood to enter the urine.

Cause	Description
Bladder infection (cystitis)	Inflammation of the bladder lining can damage small blood vessels.
Kidney or ureter stones	Movable stones can injure the mucous membranes and trigger bleeding.
Prostate diseases	Enlarged or inflamed prostate can irritate the urethra.
Bladder or kidney cancer	Tumors in the urinary tract can cause subtle or painless bleeding.
Urinary tract injuries	Trauma or medical procedures can cause temporary bleeding.
Medications	Blood thinners (e.g., aspirin, Marcumar) can increase the tendency to bleed.
Glomerulonephritis	Inflammatory kidney disease that can be accompanied by blood in the urine.

What does urine look like during a bladder infection?

Urine can visibly change during a bladder infection. This is due to inflammatory processes in the bladder that affect the composition of the urine. Typical changes involve the color, smell, and clarity of the urine.

Change	Possible cause
Cloudy urine	Increased number of bacteria, white blood cells, or proteins due to inflammation.
Dark yellow or brownish urine	Sign of high concentration or breakdown products of inflammation.
Bloody or reddish urine (hematuria)	Inflamed bladder lining can bleed, especially in severe infections.
Strong-smelling urine	Bacterial decomposition processes can cause an unpleasant, foul, or ammonia-like odor.
Foamy urine	Indication of protein in the urine, which can occur in severe infections.

When should you see a doctor for blood in the urine?

Blood in the urine (hematuria) is a serious symptom that should always be medically evaluated. Even though a bladder infection is a common cause, other diseases may also be behind it that require targeted treatment.

A doctor should be consulted immediately if:

Blood in the urine occurs without pain → May indicate serious conditions such as bladder cancer or kidney problems.
Additionally fever, back pain, or nausea occurrence → May indicate a kidney pelvis infection (pyelonephritis).
Hematuria persists for several days or recurs → Chronic inflammation or other underlying conditions may be present.
Blood clots are visible in the urine → May indicate severe bleeding or a serious infection.
Blood in the urine occurs after a physical injury → Possible indication of kidney or bladder injuries.

What tests are necessary for blood in the urine?

The following examinations can be performed to determine the cause of blood in the urine:

Urine test: Detection of blood, bacteria, or protein in the urine.
Blood tests: Examination for inflammation or kidney function.
Ultrasound of the kidneys and bladder: To detect urinary stones, tumors, or anatomical abnormalities.
Cystoscopy: Inspection of the bladder to clarify tumors or inflammation.
Computed tomography (CT) or MRI: In cases of unclear cause or suspicion of kidney disease.

How common is blood in the urine with bladder infections?

Blood in the urine (hematuria) is a possible but not always present symptom of a bladder infection. About 20–30% of women with acute cystitis report blood in their urine. This symptom is less common in men, as bladder infections are generally less frequent in them.

Can a bladder infection with blood in the urine heal on its own?

A mild bladder infection can sometimes resolve on its own if the immune system is strong enough to fight the infection. However, blood in the urine (hematuria) is a sign of a more severe inflammation of the bladder lining, so medical evaluation is recommended in these cases.

In rare cases, a mild cystitis with blood in the urine can heal on its own if:

The blood presence is minor and disappears after 1–2 days.
No other severe symptoms such as fever, severe pain, or blood clots occur.
Sufficient fluids are consumed to flush the bladder well.
The infection is detected early and supported by home remedies such as warmth, bladder teas, and herbal preparations.

How long does blood in the urine last with a bladder infection?

Blood in the urine (hematuria) can persist for varying lengths of time during a bladder infection, depending on the severity of the infection. In most cases, the blood disappears within a few days after starting appropriate treatment.

Course	Duration of hematuria	Characteristics
Mild bladder infection	1–2 days	Slight blood admixture, often with increased urge to urinate and burning.
Untreated bladder infection	Up to 1 week	Blood may persist or worsen, often with pain and strong urge to urinate.
Severe or complicated bladder infection	More than 7 days	Blood clots in the urine possible, often accompanied by fever and severe pain.
Recurrent bladder infections	Irregular	Can occur in episodes with chronic infections.
Bladder infection with kidney involvement	Longer than 1 week	High fever, flank pain, and nausea indicate a kidney infection.

Are there home remedies for blood in the urine with bladder infection?

Blood in the urine during a bladder infection can often be supported with home remedies, but these do not replace medical treatment. Especially with persistent or severe hematuria, a doctor’s visit is urgently required.

Home remedies	Effect	Application
Drink plenty of fluids	Flushes bacteria from the urinary tract and dilutes blood in the urine.	2-3 liters of water or herbal tea per day.
Bladder and kidney teas (e.g., goldenrod herb, nettle, bearberry leaves)	Anti-inflammatory and diuretic.	Drink several times daily as tea.
Cranberry juice or capsules	Can make it harder for bacteria to adhere to the bladder lining.	200-300 ml juice or capsules according to manufacturer’s instructions.
Heat (hot water bottle or sitz bath)	Promotes blood circulation, relieves cramps and pain.	Apply to the lower abdomen or take a 15-minute warm sitz bath.
D-mannose (natural sugar)	Binds bacteria in the urinary tract and supports their elimination.	Take daily as powder or capsules.
Natural anti-inflammatories (ginger, turmeric, garlic)	Antibacterial and anti-inflammatory effect.	Consume in food or as tea.