What happens when you swish oil
The mechanism is mechanical and biochemical. When you swish oil vigorously for 15-20 minutes, several things happen:
Emulsification — the oil mixes with saliva and gets pulled between teeth and along gum lines. The constant swishing action creates an emulsion that can reach areas a toothbrush might miss.
Bacterial adhesion — most oral bacteria have lipophilic (fat-attracting) cell membranes. The oil acts as a medium that bacteria adhere to. When you spit out the oil, you spit out bacteria with it. This is sometimes called the "saponification" or detergent-like effect [1].
Biofilm disruption — the mechanical action of prolonged swishing may help loosen plaque biofilm from tooth surfaces [4].
The Streptococcus mutans evidence
Streptococcus mutans is the primary bacterium responsible for dental cavities. Asokan et al. conducted a randomized, controlled, triple-blind study comparing oil pulling with sesame oil against chlorhexidine mouthwash (the clinical gold standard). After 10 days, both groups showed significant reductions in S. mutans counts in plaque and saliva. Oil pulling was statistically comparable to chlorhexidine for bacterial reduction [1].
This is a meaningful finding. Chlorhexidine is the most effective antimicrobial mouthwash available, but it has side effects with long-term use including tooth staining and taste alteration. Oil pulling showed similar antibacterial efficacy without these drawbacks.
Plaque and gingivitis
Asokan's team also studied oil pulling's effect on plaque-induced gingivitis. After 10 days of oil pulling, participants showed significant reductions in both plaque index scores and modified gingival index scores [2]. Amith et al. independently confirmed reductions in plaque and gingivitis scores with oil pulling using sunflower oil over a 45-day period [4].
Peedikayil et al. specifically tested coconut oil (the most commonly used oil today) and found significant decreases in plaque and gingival indices starting from day 7 of daily practice [3]. Coconut oil has the added property of containing lauric acid, which has known antimicrobial and anti-inflammatory effects.
How to do it
- Choose your oil — coconut oil is the most popular choice (pleasant taste, lauric acid content). Sesame oil has the most research behind it. Cold-pressed, unrefined versions of either work well.
- Use about one tablespoon — enough to swish comfortably without your mouth feeling overfull.
- Swish for 15-20 minutes — do it first thing in the morning, before eating or drinking. Gently push and pull the oil through your teeth. Don't gargle.
- Spit into the trash — not the sink (oil can clog pipes over time). The oil will be thinner and whitish when you're done.
- Rinse your mouth with warm water, then brush your teeth as normal.
Important: oil pulling is not a replacement for brushing and flossing. It's a supplement to standard oral hygiene, not a substitute. No study has positioned it as a standalone practice [1][2].
Evaluating the evidence
The oil pulling research is stronger than many alternative health practices, but has clear limitations:
Strengths: Asokan's S. mutans study was randomized, controlled, and triple-blind — a rigorous design [1]. Multiple independent groups have confirmed plaque and gingivitis reductions [2][3][4]. The mechanism (lipophilic bacterial adhesion to oil, mechanical biofilm disruption) is biologically plausible.
Limitations: Most studies have small sample sizes (20-60 participants). The majority of controlled research comes from Indian dental institutions, and broader replication from diverse research groups would strengthen the evidence. Long-term studies (beyond a few weeks) are largely absent. The optimal oil type, duration, and frequency have not been systematically compared.
What's clear: oil pulling measurably reduces S. mutans counts, plaque scores, and gingivitis markers in the short term [1][2][3][4]. It appears comparable to chlorhexidine for bacterial reduction without the side effects [1].
What's not clear: whether these short-term reductions translate to fewer cavities or less periodontal disease over months and years. The cavity and gum disease prevention outcomes that actually matter to patients have not been directly measured in oil pulling studies.
The practice is low-risk (the only meaningful caution is not to swallow the bacteria-laden oil) and low-cost. For anyone willing to spend 15-20 minutes each morning on it, the existing evidence supports it as a useful addition to brushing and flossing — not a replacement.