Overdose deaths due to legal and illicit drug use and abuse are on the rise. All the experts agree. Defining what is a drug overdose death  or — when more than one drug is found in the bloodstream — which drug was responsible is less clear. (“No snowflake in an avalanche ever feels responsible.” — Stanisław Jerzy Lec, 20th-century Polish aphorist, and poet.)

If the cause of death is the interaction of two or more drugs, can the death be attributed to either drug alone? If you want to demonize one, I guess.

Recently the Food and Drug Administration released a report claiming that kratom, a green powder derived from a Southeast Asia plant (a coffee relative) — and sold as an herbal dietary supplement, not a drug — was not a safe alternative to opioid medicines. In fact, FDA said, it is an opioid and was associated with 44 deaths since 2011. Presumably, they meant overdose deaths, but in almost all cases other drugs were found in the bodies.

Leo Beletsky, an associate professor of law and health sciences at Northeastern University, said: “The only times we’ve found kratom to be involved in adverse events are times when even in the absence of kratom, you’d still have really deleterious effects.”

How can doctors determine if someone has died of a drug overdose, and if so, which drug or drugs were responsible? If one drug is considered lethal and the other isn’t, you can make an educated guess.

A few years earlier there was concern that gabapentin, a non-narcotic and non-controlled substance, was becoming a dangerous overdose drug when it was detected in the bodies of almost a third of overdose deaths in Kentucky. No breakdown of what other drugs also were in the bodies was provided, but overdose death by gabapentin alone was believed to be impossible. (Some opioid users take gabapentin to heighten the high.)

Despite evidence that it is impossible to die of an overdose of marijuana, every now and then cannabis opponents dredge up a case where marijuana is found in the body of a dead person, and overdose is alleged.

What difference does it make? Dead is dead. Well, it matters in lawsuits for wrongful death.

A 2010 Time magazine article cited Berkeley pathologist Steven Karch, who studied drug-related death for decades, and was called to testify in the trial of a doctor-and-nurse couple accused of operating a pill mill that killed almost 70 patients. In effect, he said that “in most instances of drug overdose, the currently available medical technology cannot accurately determine whether or which drugs caused death.”

Of greater concern than who is responsible is stopping the overdose deaths in the first place. Seek drug rehab if you can’t stop on your own or if withdrawal is too painful.

Kratom, gabapentin, and marijuana may not be 100 percent safe, but the best evidence is that they are less deadly than many legal but lethal substances subject to abuse, including alcohol. If you claim that drugs are more deadly than they are, it hurts your credibility when those you are trying to persuade learn otherwise. Stick to the facts.