What are the weird smells after having COVID?

September 28, 2025 •

4 min read

According to research published by the National Institutes of Health, a significant portion of people who had COVID-19 experience an altered sense of smell, known as parosmia. So, what are the weird smells after having COVID, and what causes this disturbing sensory distortion?

Quick Summary

Weird smells after having COVID, scientifically termed parosmia and phantosmia, are caused by damage to the nerves in the olfactory system during infection. This can result in once-familiar scents, like coffee or food, smelling foul, and even phantom odors appearing out of nowhere. Many patients find relief through a practice called olfactory training.

Key Points

Parosmia and Phantosmia: The weird smells after COVID are scientifically known as parosmia (distorted smells) and phantosmia (phantom smells).
Nerve Damage: The cause is believed to be damage to the support cells of the olfactory system, which affects how nerves regenerate and communicate with the brain.
Common Triggers: Everyday items like coffee, onions, garlic, and grilled meat can smell rotten, foul, or chemical.
Olfactory Training: A highly recommended, low-risk treatment involves mindfully sniffing a series of scents like eucalyptus and rose to help retrain the nervous system.
Coping Strategies: Lifestyle changes such as eating blander foods or at cooler temperatures can help manage triggers, alongside seeking emotional support.
Safety First: Altered smell perception can reduce your ability to detect hazards like gas leaks or spoiled food, so rely on alarms and check dates carefully.

What is Parosmia and Phantosmia?

After a COVID-19 infection, many people's sense of smell can become distorted, a condition called parosmia. It's often described as once-pleasant or neutral smells—such as coffee, garlic, and onions—transforming into something unpleasant, often burnt, rotten, or chemical-like. Another related condition, phantosmia, involves smelling odors that aren't actually there, such as the persistent smell of smoke. These post-viral olfactory disturbances have significantly impacted the quality of life for many long COVID sufferers, affecting their diet, mental health, and social interactions.

The Science Behind Altered Smells

Scientists now have a clearer understanding of why the SARS-CoV-2 virus triggers these olfactory issues. Unlike typical viruses that cause smell loss through simple nasal congestion, COVID-19 directly attacks the support cells in the olfactory epithelium—the tissue in the nose responsible for detecting smells. While the main olfactory neurons are generally spared, the inflammation caused by the virus attacking the support cells can lead to an abnormal regeneration of the nerves. This improper rewiring of the nervous system is thought to be the root cause of the distorted and phantom smells experienced by many.

Common Triggers and Distorted Scents

For those with parosmia, certain everyday smells can become unbearable. Identifying these triggers can help individuals manage the condition and avoid unpleasant experiences. Common triggers include:

Roasted and fried foods: Coffee, grilled meat, and other browned foods often trigger a rotten or sewage-like smell.
Aromatics: Onions, garlic, and chives are frequently reported to smell rancid or chemical.
Hygiene products: Toothpaste, deodorant, and other scented products can smell distorted and unpleasant.
Household items: Certain cleaning products or gas smells can also trigger a distorted sensory response.

Management Strategies for Distorted Smells

While there is no guaranteed instant cure for parosmia or phantosmia, several strategies can help manage and potentially improve symptoms over time. Patients often recover slowly, with most seeing improvement within two years.

Olfactory (Smell) Training: This involves mindfully smelling a set of four different strong scents twice a day for several months. Common choices include rose, eucalyptus, lemon, and clove essential oils. The goal is to stimulate and retrain the olfactory system by actively focusing on and recalling the memory of each smell.
Dietary Adjustments: Many individuals find it helpful to eat blander foods or serve meals cold or at room temperature. Heat releases more volatile compounds, which can intensify distorted smells. By reducing the aromatic complexity of food, patients can make eating more tolerable.
Steroid Nasal Sprays: Intranasal steroids may help reduce inflammation in the nasal passages, though their success in treating COVID-induced anosmia is limited. A healthcare professional can determine if this is a suitable option.
Mental Health Support: The distress and isolation caused by parosmia can impact mental health, potentially leading to anxiety and depression. Support groups and therapy can provide emotional support and coping mechanisms for this challenging condition.
Safety Precautions: Since a distorted sense of smell can mask dangerous odors like gas or smoke, it is crucial to ensure that smoke alarms and carbon monoxide detectors are functional and regularly tested.

Comparison of Olfactory Conditions After COVID-19

This table outlines the differences between the three main olfactory dysfunctions seen after a COVID-19 infection.


Condition	Description	Typical Onset After Infection	Smell Perception
Anosmia	Complete loss of smell	Often during the initial infection	No smell detected
Hyposmia	Decreased sense of smell	Can occur during or after infection	Faint or reduced smell
Parosmia	Distorted sense of smell	Weeks to months after infection	Normal odors smell unpleasant or chemical
Phantosmia	Smelling phantom odors	Weeks to months after infection	Smelling odors that are not present

Conclusion

Experiencing bizarre and unpleasant odors after a COVID-19 infection is a distressing but common reality for many. Parosmia and phantosmia are the result of damage to the olfactory system, but thankfully, this condition is often temporary. While challenging, strategies like olfactory training, dietary modifications, and seeking mental health support can help manage symptoms and promote recovery. If you are struggling with persistent or severe olfactory disturbances, it is important to consult a healthcare professional to discuss your options and rule out other potential causes. For more information on dealing with changes in smell, consider exploring reputable health resources like the Monell Chemical Senses Center.

Potential Complications of Persistent Smell Disturbances

Beyond the daily frustrations, persistent olfactory disturbances carry certain risks that necessitate careful management. The inability to correctly detect smells can pose safety hazards related to food spoilage and environmental dangers. It's crucial for affected individuals to rely on safety measures like checking expiration dates and ensuring fire alarms are in good working order. Additionally, the emotional toll of parosmia and phantosmia, including the loss of pleasure from food and the isolation from social situations, can lead to mood disorders. Recognizing the psychological impact is an important step toward finding comprehensive care and support.

How the Sense of Smell Heals

Recovery from COVID-induced parosmia or phantosmia depends on the healing of the delicate olfactory tissues. The process involves the regeneration and reconnection of nerve pathways, which is often slow and can sometimes be faulty, leading to distorted smells before full function is restored. Olfactory training is believed to help guide this healing process by stimulating the nerves with consistent, familiar sensory input. The brain's neuroplasticity plays a key role, gradually relearning how to correctly interpret smell signals. While the timeline for recovery varies widely, consistent effort and patience are key components of the healing journey.

Frequently Asked Questions

The persistent, weird burnt smell after COVID is a common symptom of parosmia, a condition where once-normal smells are distorted into unpleasant or foul odors. This happens because of damage and irregular regeneration of the nerve cells responsible for smell.

The duration varies greatly among individuals. For some, the weird smells may resolve within a few weeks, but for others, symptoms can last for several months or even years. Many people see significant improvement within 18 to 24 months, especially with interventions like smell training.

While stress doesn't cause parosmia, the psychological distress and anxiety associated with having a distorted sense of smell can certainly exacerbate the condition and make it feel more overwhelming. Seeking mental health support is often a crucial part of management.

Yes, research indicates that olfactory training can be an effective way to help retrain the brain to correctly identify smells. It's a gradual process that requires patience and consistency, but it has shown good results for many people recovering from post-viral smell loss.

Coffee is a common parosmia trigger because it has a complex aroma profile. The regeneration of olfactory nerves can be faulty, causing the brain to misinterpret these complex aromatic compounds. As a result, the rich, familiar scent of coffee can be perceived as rotten, sewage-like, or chemical.

Many people with parosmia find that heavily cooked, fried, or highly aromatic foods are the worst triggers. Common culprits include roasted meat, coffee, garlic, and onions. It can be helpful to keep a food diary to identify your personal triggers. Eating cooler or blander foods is often easier.

No, while fluctuations in smell perception can occur during recovery, a sudden and complete loss of smell (anosmia) or a major setback should prompt a consultation with a doctor. This could indicate a new infection or another underlying issue.