Matatabi (木天蓼) is the Japanese name for silvervine, Actinidia polygama, a mountain vine from Japan and East Asia whose galled fruit affects cats much the way catnip does. What it does not mean is "travel again", despite that being the story almost every English page repeats.
Almost every English page about silvervine tells the same story: a weary traveller ate the plant, recovered, and was able to travel again, 又 mata, 旅 tabi. It is a lovely story. It is also a folk etymology, and the oldest Japanese records contradict it.
How do you pronounce matatabi?
Four even syllables: ma-ta-ta-bi, roughly "mah-tah-tah-bee". Every vowel is short and clean, and Japanese does not stress one syllable over the others the way English instinctively wants to. English speakers commonly compress it to matabi, dropping the third syllable, which is why a good number of people end up searching for the word that way. Same plant, one syllable short.
What is wrong with the "travel again" story?
The spelling, and it is decisive.
The earliest attestations of the word are not matatabi at all. They are watatabi. The 918 medical text Honzō Wamyō records it as 和多々比, and the 927 Engishiki records 和太太備. Both begin wa, not mata.
If the word started as watatabi, it cannot have been built from 又 mata. The traveller story only works on the modern pronunciation, which means it was reverse-engineered after the fact. The Japanese etymological dictionary Gogen Yurai puts it about as bluntly as a reference work can, calling it an exaggerated pun on the plant's supposed tonic effect and entirely made up.
One thing worth saying, since it would be easy to sneer in the wrong direction: this is not a Western misunderstanding. The story circulates widely in Japan too, usually hedged with "it is said that". English retellings tend to drop the hedge and state it flatly.
So where does the word come from?
Honestly, nobody has settled it.
The most commonly favoured explanation is that it comes from Ainu. The Japanese encyclopaedia Nihon Daihyakka Zensho states this outright. We would put it more carefully than they do, because the details wobble: the Ainu source word is transcribed in different places as マタタムブ and マタタンプ, and its second element has been glossed both as tortoise shell and as a wrapped gift, by different scholars. A dictionary form in the Akita dialect, matanbu, is often cited alongside it.
Other proposals exist, including a reading of watatabi as "not-genuine knotweed fruit", and an early suggestion from the scholar Kaibara Ekiken around 1700 that Gogen Yurai dismisses for lack of supporting examples.
So the fair summary is this: the travel-again story is wrong, an Ainu origin is the leading candidate, and the truth is genuinely unsettled. We would rather leave it there than tidy it into a neat sentence that happens to be false.
Why is it written 木天蓼 when that says nothing like "matatabi"?
Because those characters are not Japanese in origin. 木天蓼 is a kanmei, a Chinese materia medica name borrowed wholesale, first appearing in the Tang dynasty pharmacopoeia Xinxiu Bencao. Japanese then attached its own existing word to the imported characters and read the whole compound as a unit.
So the characters do not spell matatabi phonetically. They are a label, and the reading is glued on. Read with their Sino-Japanese pronunciation, mokutenryō, the same characters refer to the dried crude drug rather than the living plant.
And the lump on the fruit?
Here the language gets specific in a way English does not.
The valued material is not the tidy fruit but the deformed one, a gall. In Japanese a gall is 虫こぶ mushikobu or 虫癭 chūei, and the galled matatabi fruit has its own name, マタタビミフクレフシ.
The insect responsible is a gall midge, Pseudasphondylia matatabi, in Japanese マタタビミタマバエ. It lays in the flower bud, the fruit grows misshapen around it, and that misshapen fruit is the one that goes into the traditional preparation.
Small pedantic warning if you go reading further: even Japanese sources get the insect wrong. The Japanese Wikipedia article contradicts itself, naming a fruit fly in one section and the correct gall midge in another, and at least one prefectural government page repeats the error.
Is matatabi the same as catnip?
No, and the distinction is the practical part. Catnip is Nepeta cataria, a mint. Silvervine is Actinidia polygama, a relative of the kiwifruit. Different families entirely, which is exactly why a cat can ignore one and lose its composure over the other. Roughly a third of cats do not respond to catnip, and most of those do respond to silvervine. We have compared all four of the common plants if you want the fuller picture.
Two things to avoid saying
"Japanese catnip." You will see it used for matatabi. See above: not the same plant, not the same family.
"Matatabi means travel again." Also see above.
Why we care about this at all
Every product we make carries a real Japanese word, and the tag tells you what it means. That is a promise we would rather keep properly than decoratively. It would have been easy to print the traveller story on the packaging for our Matatabi Ball, and it would have been charming, and it would have been wrong.
If you want the part that actually matters to your cat, the galled fruit business is not trivia. It is the difference between a silvervine product that works and one that does not. And if you have tried silvervine and got nothing at all, the form is usually the reason rather than the cat.
Sources: 語源由来辞典 (gogen-yurai.jp) on またたび; 本草和名 (918) and 延喜式 (927) attestations; 日本大百科全書 on the Ainu derivation; 精選版日本国語大辞典 on 木天蓼 as a 漢名. Scientific name Actinidia polygama (Siebold & Zucc.) Planch. ex Maxim., verified at IPNI. Gall midge Pseudasphondylia matatabi (Yuasa & Kumazawa, 1938).