Stink bugs and bed bugs are completely different insects that look nothing alike, behave differently, and pose very different problems in your home. The confusion usually starts because both are common household pests, both are brown, and both belong to the same broad insect order (Hemiptera, or “true bugs”). But that’s where the similarities end. One feeds on plants and wanders indoors by accident. The other feeds on your blood while you sleep.
How They Look Side by Side
The easiest way to tell these two apart is size and shape. The brown marmorated stink bug, the species most people encounter, is roughly 17 mm long, about the size of a dime. It has a wide, shield-shaped body with a flat back, mottled brown coloring, and visible antennae. Adult bed bugs are about 6 mm long, closer to an apple seed. They’re oval, flat (when unfed), and a uniform reddish-brown. After feeding, bed bugs swell and become more elongated.
Stink bugs also have visible wings and can fly. Bed bugs are wingless and move only by crawling. If you see a brown bug flying around your living room or clinging to a window screen, it’s not a bed bug.
What They Eat
This is the most important difference. Stink bugs are herbivores. They feed on fruits, vegetables, and ornamental plants using piercing mouthparts designed for plant tissue. They have zero interest in biting humans. They enter homes in the fall looking for a warm place to overwinter, not looking for a meal.
Bed bugs are obligate blood feeders. Every member of the bed bug family feeds exclusively on blood, and the common bed bug specifically targets humans. Each immature bed bug must take a blood meal to develop into the next life stage, and adults need regular blood meals to reproduce. They live close to their host, typically in mattress seams, bed frames, and nearby furniture, and come out at night to feed. A single bed bug will probe your skin several times to find a good blood vessel, which is why bites often appear in clusters or lines. Once it settles on a spot, it feeds for 5 to 10 minutes.
Bites and Health Effects
Stink bugs don’t bite. Their only defense mechanism is chemical: when threatened or crushed, they release a pungent secretion from glands on their abdomen. The smell is often compared to a skunk. The secretion contains aldehydes and other compounds that can cause a burning sensation on skin or mucous membranes if you handle the bug carelessly. In rare cases, people with sensitivities may develop mild contact dermatitis from the fluid, but this isn’t a bite and it’s not dangerous.
Bed bug bites are a different story. Most people don’t feel the bite when it happens because bed bugs inject an anesthetic along with an anticoagulant that keeps blood flowing. You typically discover bites the next morning as red, itchy welts. Reactions vary widely. Some people show no marks at all, while others develop large, inflamed welts that itch intensely for days. The bites themselves don’t transmit diseases, but heavy scratching can lead to secondary skin infections. The psychological toll of a bed bug infestation, including anxiety and sleep disruption, is also well documented.
Where You’ll Find Them
Stink bugs are seasonal invaders. They spend spring and summer outdoors feeding on plants, then seek shelter in walls, attics, and window frames as temperatures drop in autumn. On warm winter days, they sometimes emerge inside the house, congregating near windows and light sources. They don’t breed indoors, don’t build nests in your furniture, and don’t establish permanent colonies in your home. Once spring arrives, they leave.
Bed bugs are year-round residents that thrive indoors. They hide in mattress seams, box springs, headboards, baseboards, and even behind electrical outlet covers. They’re primarily nocturnal and stay hidden during the day, which is why infestations can grow for weeks before you notice. Unlike stink bugs, bed bugs don’t wander in from outside. They hitch rides on luggage, used furniture, clothing, and other items that move between locations.
The Smell Factor
Stink bugs are famous for their odor, and it’s earned. The chemical defense spray contains long-chain alkanes, aldehydes, and esters that produce a sharp, acrid smell strong enough to linger on surfaces. If the secretion contacts your mouth or tongue, it can cause a burning sensation and chemical taste lasting up to 20 minutes, followed by localized numbness that persists for one to two hours. The takeaway: don’t crush stink bugs with bare hands, and don’t let curious pets mouth them.
Bed bugs also produce a smell, though most people only notice it in heavy infestations. It’s often described as musty or sweetish, sometimes compared to coriander or overripe raspberries. If you notice an unusual sweet, musty odor near your bed along with small rust-colored spots on your sheets, that combination is a strong indicator of bed bugs.
How to Get Rid of Each
Stink Bugs
Indoor pesticides are largely ineffective against stink bugs. The best approach is physical removal and exclusion. Vacuum them up or pick them up by hand (use a tissue to avoid the smell). A simple homemade trap works well: fill a roasting pan with soapy water, place it in a dark room, and shine a light toward it. Stink bugs are attracted to the light and will fall into the water. Killing or vacuuming them may release their odor, but contrary to popular belief, this smell does not attract more stink bugs.
Long-term prevention means sealing entry points. Check around doors, windows, and foundation cracks, and close any gaps. Correctly timed outdoor perimeter treatments with pesticides can help if applied before stink bugs begin migrating indoors in fall, but indoor spraying is generally a waste of time and money.
Bed Bugs
Bed bugs are far harder to eliminate. They’re resistant to many common pesticides, reproduce quickly, and hide in places that are difficult to reach. Professional treatment is almost always necessary. The two main approaches are heat treatment, where a room is heated to temperatures lethal to all life stages, and targeted chemical treatment using products specifically labeled for bed bugs. Most infestations require multiple treatment visits over several weeks.
Prevention focuses on vigilance rather than sealing your home. Inspect hotel rooms before unpacking. Check used furniture carefully before bringing it inside. Use mattress encasements to eliminate hiding spots. If you suspect an infestation, act quickly. A small population of bed bugs can explode into a major problem within a couple of months.
Quick Comparison
- Size: Stink bugs are roughly 17 mm (dime-sized). Bed bugs are about 6 mm (apple seed-sized).
- Shape: Stink bugs are shield-shaped with visible wings. Bed bugs are flat ovals with no wings.
- Diet: Stink bugs eat plants. Bed bugs feed on blood.
- Biting: Stink bugs don’t bite humans. Bed bugs bite at night, often in clusters.
- Smell: Stink bugs release a strong skunk-like odor when disturbed. Bed bugs produce a faint musty smell in heavy infestations.
- Season: Stink bugs invade homes in fall and leave in spring. Bed bugs live indoors year-round.
- Removal: Stink bugs can be vacuumed and sealed out. Bed bugs typically require professional extermination.